Athletes participating in professional soccer are at an increased risk for long-term neurologic disease due to exposure of repetitive head trauma (MacKay et al., 2019). Recent studies have confirmed cases of dementia and chronic traumatic encephalopathy in retired professional soccer players who played during 1966 (McKee et al., 2014; Hales et al., 2014; Bieniek et al., 2015; Ling et al., 2017; Grinberg et al., 2016). It is suspected that repetitive sub concussive impacts from heading may be a contributing factor to the development of chronic neurological deficits (Matser et al., 1998; Witol & Webbe, 2003). It is unknown if current soccer players are at similar risk of brain trauma. Differences of soccer balls, rules changes, and evolution of the game, may have influenced total frequency and impact magnitude of heading. A comparison of frequency and impact magnitude of heading between 1966 and 2018, highlights the potential risk of chronic neurodegeneration in professional soccer players. Ten 1966 and ten 2018 FIFA World Cup matches were randomly chosen for video analysis. Total frequency of headers were documented for each game. Header exemplar reconstructions were completed in the laboratory using a 1966 Slazenger Challenge and 2018 Telstar 18 ball. A pneumatic linear impactor and projectile launcher were used to hit the ball and impact a Hybrid III head form to measure dynamic head response. A finite element model was then used to determine heading magnitudes as measured by Maximal Principal Strain (MPS). The study revealed there were no significant differences in overall frequency of headers between the 1966 and 2018 games. The year 2018 had significantly higher frequency of headers in the medium MPS category while, 1966 had significantly higher frequency in the high category. There were no significant differences of linear acceleration, angular acceleration, and MPS values when comparing the 2018 dry and 1966 dry ball at the same velocity and location. Current athletes who are heading the 2018 Telstar 18 are sustaining similar frequency and magnitudes of heading as athletes in 1966 under the same velocity and impact locations.

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Over the last 20 years, navigation has almost become synonymous with satellite positioning, e.g. the Global Positioning System (GPS). On land, sea or in the air, on the road or in a city, knowing ones position is a question of getting a clear line of sight to enough satellites. Unfortunately, since the signals are extremely weak there are environments the GPS signals cannot reach but where positioning is still highly sought after, such as indoors and underwater. Also, because the signals are so weak, GPS is vulnerable to jamming. This thesis is about alternative means of positioning for three scenarios where gps cannot be used. Indoors, there is a desire to accurately position first responders, police officers and soldiers. This could make their work both safer and more efficient. In this thesis an inertial navigation system using a foot mounted inertial magnetic mea- surement unit is studied. For such systems, zero velocity updates can be used to significantly reduce the drift in distance travelled. Unfortunately, the estimated direction one is moving in is also subject to drift, causing large positioning errors. We have therefore chosen to throughly study the key problem of robustly estimating heading indoors. To measure heading, magnetic field measurements can be used as a compass. Unfortunately, they are often disturbed indoors making them unreliable. For estimation support, the turn rate of the sensor can be measured by a gyro but such sensors often have bias problems. In this work, we present two different approaches to estimate heading despite these shortcomings. Our first system uses a Kalman filter bank that recursively estimates if the magnetic readings are disturbed or undisturbed. Our second approach estimates the entire history of headings at once, by matching integrated gyro measurements to a vector of magnetic heading measurements. Large scale experiments are used to evaluate both methods. When the heading estimation is incorporated into our positioning system, experiments show that positioning errors are reduced significantly. We also present a probabilistic stand still detection framework based on accelerometer and gyro measurements. The second and third problems studied are both maritime. Naval navigation systems are today heavily dependent on GPS. Since GPS is easily jammed, the vessels are vulnerable in critical situations. In this work we describe a radar based backup positioning system to be used in case of GPS failure. radar scans are matched using visual features to detect how the surroundings have changed, thereby describing how the vessel has moved. Finally, we study the problem of underwater positioning, an environment gps signals cannot reach. A sensor network can track vessels using acoustics and the magnetic disturbances they induce. But in order to do so, the sensors themselves first have to be accurately positioned. We present a system that positions the sensors using a friendly vessel with a known magnetic signature and trajectory. Simulations show that by studying the magnetic disturbances that the vessel produces, the location of each sensor can be accurately estimated.

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International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / The Global Positioning System (GPS) is a very accurate, all-weather, world wide three dimensional navigation system and it has been used in almost every field related to positioning and navigation. This paper presents a new application of GPS technology - personal positioning and navigation system. It combines VP ONCORE receiver OEM (Original Equipment Manufacture) board and an intelligent system controller, with a keyboard and a programmable LCD as its peripherals. This system can realize rich navigation functions and satisfy the need of personal use.

Revised 10/2015; Originally published 10/2013. / 2 pp. / Grain yield, test weight, and other characteristics of barley, durum, and wheat varieties are provided in this publication

One important part of inertial navigation is the estimation of the direction relative to the Earth’s geographic North Pole, the so called heading. In this project, a gyroscope and an accelerometer were used together in an Extended Kalman Filter with a quaternion as the state space variable, representing the attitude. Given the attitude of the system, measurements from a magnetometer were rotated to a horizontal coordinate frame in order to calculate the direction toward Earth’s magnetic North Pole. Comparing this direction with the angle toward the Geographic North Pole given by a GPS, the local magnetic declination was estimated with the purpose of correcting the heading in the future. Different methods for detecting disturbances on the magnetometer in order to automatically decide when it is to be trusted was discussed and evaluated. Routines for easily performing sensor calibration was created. The outcome of the project was a well working attitude estimation, simply performed calibration routines and a set of methods working together to detect magnetometer disturbances. / En viktig del av ett tröghetsnavigeringssystem är skattningen av riktningen relativt jordens geografiska nordpol, den så kallade bäringen. I detta projekt användes ett gyroskop och en accelerometer tillsammans i ett Extended Kalman filter med en quaternion som tillståndsvariabel för att representera attityden. Givet systemets attityd roterades mätningar från en magnetometer till ett horisontellt koordinatsystem för att beräkna riktningen mot magnetiska nordpolen. Genom att jämföra denna riktning med vinkeln mot geografiska nordpolen kunde den lokala magnetiska deklinationen skattas för att sedan användas i framtiden för att korrigera bäringen. Olika metoder för att detektera störningar på magnetometern för att automatiskt bestämma när den är störd diskuteras och utvärderas. Rutiner för att enkelt kalibrera sensorerna skapades. Projektets resultat var en väl fungerande attitydestimering, enkla kalibreringsmetoder samt ett par metoder för att detektera störningar på magnetometern.

Background: Heading is an important part of soccer, yet recent research has indicated that cumulative effects of repetitive heading may cause sub-concussive injury (Koerte et al., 2015). Objective: The current study aimed to prospectively investigate the effects of repetitive, intentional heading in soccer practice on brain structure and cognitive function using a within-subjects design. Methods: Participants included 11 soccer players (M=20.09, SD=2.88) that were examined immediately pre and post heading practice. Magnetic resonance imaging data were acquired on a 3T GE Scanner with diffusion tensor imaging (DTI). Behavioural measures were also completed pre and post soccer heading and included the Sideline Concussion Assessment Tool 3 (SCAT-3) and several short-computerized executive function tasks. An accelerometer was used to measure the force of the impact during soccer heading. Heart-rate data was collected on Polar Monitors. DTI analyses were completed using FSL’s Tract Based Spatial Statistics to examine changes in both fractional anisotropy (FA) and mean diffusivity (MD) due to heading the soccer ball. The current study investigated microstructural changes and behavioural performance in young soccer players. Heart rate variability data were not available for analyses due to technical difficulties. Results: Heading impacts were not greater than 10g. At this level of impact, there were no significant pre-post heading differences in either FA or MD. There were no significant differences between pre and post heading in the three behavioural tasks. Additionally, there were no significant differences in SCAT-3 scores between groups. Some practice effects were demonstrated in one behavioural task and a section of the SCAT-3. Conclusion: The current work shows initial evidence that repetitive heading in soccer in a practice setting does not cause changes in brain structure or cognitive function. Future research should investigate heading in games and sex differences with a greater sample size. / Graduate

The contents of Section 2.2 and Chapter 4 first appeared in proceedings of the 12th International Conference on Web Information Systems and Technologies, 2016 (www.webist.org). The contents of Section 2.3 and Chapter 5 first appeared in DBSJ Journal, vol. 14, article no. 2, March 2016. The contents of Section 2.5 and Chapter 7 first appeared in proceedings of the 11th Asia Information Retrieval Societies Conference, Lecture Notes in Computer Science, vol. 9460, pp. 188-200, 2015 (The final publication is available at link.springer.com). / 京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第19854号 / 情博第605号 / 新制||情||105(附属図書館) / 32890 / 京都大学大学院情報学研究科社会情報学専攻 / (主査)教授 田島 敬史, 教授 田中 克己, 教授 吉川 正俊 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM

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