Sweat

Over the last years continuous and non-invasive measurement techniques to gain insight in health and performance have become popular. These continuous and non-invasive biochemical measurement techniques are commonly manifested in wearable sensors for which sweat is the most preferred bodily fluid to use due to its easy and continuous accessibility and rich biomarker content. Currently sweat sensor developments are largely technology driven while the scientific foundations for the monitoring of health and performance via sweat often are lacking. In the current thesis we aimed to contribute to knowledge on how sweat composition is affected and how to measure sweat in a reliable way. Direct relations between blood and sweat are often assumed. For many components in blood it has already been established how their concentrations relate to specific diseases or sports performance. We have shown that during submaximal exercise relations between blood and sweat sodium, chloride, potassium, lactate, ammonia and glucose were non-significant. Therefore, it may be more relevant to establish what information is in sweat itself and how it varies within individuals. Subsequently, we observed that sweat becomes less salty during heat acclimation. In this way, sweat composition could provide information about the physical state of the body (in this case heat acclimation). By obtaining such knowledge, we hope that athletes and/or healthcare could be eventually be provided with meaningful feedback about physiological parameters based on sweat

LOWER EXTREMITY JOINT LOADING IN CARVED SKI AND SNOWBOARD TURNS

Skiing and snowboarding are the most popular winter sports in the Alps and are practiced by an increasing number of people. With the increasing number of practitioners, also the number of injuries increased. In skiing, most injuries are located in the lower extremities and in snowboarding about 1/3 of all injuries involve the lower extremities. To improve safety aspects in skiing and snowboarding, more knowledge is required about loading on the lower extremities joints. In the current paper, the loading at the knee and ankle joint in skiing and snowboarding are compared. Results showed that loading is more evenly distributed between the legs in snowboarding. Furthermore, the highest average and resultant peak forces at the knee were found in the outside leg in skiing. The highest forces at the ankle joint were observed at the outside leg in skiing, whereas the largest moments were found in the rear leg in snowboarding

EXPERIMENTAL SETUP TO COLLECT INPUT DATA FOR CALCULATING LOADING ON THE LOWER EXTREMITIES IN SKIING AND SNOWBOARDING

Little is known about the loading on the lower extremities in skiing and snowboarding. The reason for this is the difficulty to collect representative 3D kinetic and kinematic data which serves as input to calculate the loading parameters. Field studies in alpine skiing and snowboarding are essential to collect representative data. Full 3D movement reconstruction requires at least three markers in sight of at least two cameras for each segment during the complete movement. It is difficult to fulfill this demand, due to several reasons. The purpose of this study is to describe the experimental setup to collect representative 3D kinetic and kinematic data. A new kinematical method that allows full 3D movement reconstruction with a reduced marker set is introduced. Furthermore, the measuring device for kinetic data is validated. Results show that the proposed experimental setup provides appropriate kinetic and kinematic data in skiing and snowboarding

KINEMATICS OF THE UPWARD JUMPING THROW IN HANDBALL - COMPERISON OF PLAYERS WITH DIFFERENT LEVEL OF PERFORMANCE

The purpose of this study was to compare the kinematics and the ball velocity of the upward jumping throw in handball of three groups with different level of performance. Significant differences between the groups were founded for the ball velocity, the segment velocity of the finger and wrist, the angle range of the shoulder flexion and extension and the maximal angular velocity of the shoulder flexion, extension and internal rotation, the elbow flexion and the ulnar deviation of the wrist. Therefore the main caused of an increased ball velocity seems to be an increasing of the angular velocity of the shoulder, especially the shoulder flexion, the elbow extension and the ulnar deviation of the wrist

THE ACCURACY OF 3D KINETIC AND KINEMATIC DATA USED FOR JOINT LOADING ANALYSIS IN SKIING AND SNOWBOARDING

Almost 50% of all skiing accidents in men and more then 70% of all skiing accidents in women concerned the lower extremities. In snowboarding about a third of all accidents concerned the lower extremities in both men and women (Burtscher et al., 2003). These high percentages afford systematic research to determine joint loading on the lower extremities in skiing and snowboarding. However, so far only rough estimations of joint loading are reported (van den Bogert et al., 1999; Quinn & Mote, 1992). More precise values would be possible by inverse dynamic analyses. These require representative 3D kinetic and kinematic data which serve as input for the inverse dynamic model to calculate the loading parameters. Therefore, the goal of this presentation is to give an overview and validation of the methodological procedures used in this study to collect and analyse 3D kinetic and kinematic data to determine the loading parameters

WIRELESS EMERGENCY PROBE MESSAGE

The techniques described herein leverage The Institute of Electrical and Electronics Engineers (IEEE) 802.11ax probe request messages to encode an Emergency Beacon (Request for Help) within the initial non-Access-Point (AP) station’s (client’s) probe request packets which would notify the AP that a client is in distress and to notify Emergency Services (via text-to-911 and provide e911 location information). This new capability allows any 802.11ax AP to receive emergency beacons, regardless of how “closed” the networks are on that AP, thereby allowing any wireless client the ability to reach out for help and allowing the AP to relay that information onward towards emergency services

Manipulation of the Bitcoin market: an agent-based study

Fraudulent actions of a trader or a group of traders can cause substantial disturbance to the market, both directly influencing the price of an asset or indirectly by misinforming other market participants. Such behavior can be a source of systemic risk and increasing distrust for the market participants, consequences that call for viable countermeasures. Building on the foundations provided by the extant literature, this study aims to design an agent-based market model capable of reproducing the behavior of the Bitcoin market during the time of an alleged Bitcoin price manipulation that occurred between 2017 and early 2018. The model includes the mechanisms of a limit order book market and several agents associated with different trading strategies, including a fraudulent agent, initialized from empirical data and who performs market manipulation. The model is validated with respect to the Bitcoin price as well as the amount of Bitcoins obtained by the fraudulent agent and the traded volume. Simulation results provide a satisfactory fit to historical data. Several price dips and volume anomalies are explained by the actions of the fraudulent trader, completing the known body of evidence extracted from blockchain activity. The model suggests that the presence of the fraudulent agent was essential to obtain Bitcoin price development in the given time period; without this agent, it would have been very unlikely that the price had reached the heights as it did in late 2017. The insights gained from the model, especially the connection between liquidity and manipulation efficiency, unfold a discussion on how to prevent illicit behavior