A novel technology, the Magneto-articulography for the Assessment of Speech Kinematics (MASK) system, which measures brain activity and oromotor movement simultaneously, was validated for its speech tracking capabilities. MASK has not been systematically tested, so its movement tracking accuracy and practicality for research was still unknown. An error testing and mapping protocol is developed to validate MASK accuracy against established electromagnetic articulography (EMA) speech tracking systems. Data from human speech experiments are also compared. MASK exhibited higher positional error and fluctuation than EMA, and more inconsistent distribution of errors. Error mapping and potential error correction protocols were also developed. MASK spatial and temporal resolutions were found insufficient for precise tracking of small and quick articulatory movements. MASK requires much improvement to reach the capabilities of EMA. Further investigation into numerical instabilities of the position calculation algorithms is encouraged. This project provides the first assessment of MASK, which may advance speech research for future applications.

A novel technology, the Magneto-articulography for the Assessment of Speech Kinematics (MASK) system, which measures brain activity and oromotor movement simultaneously, was validated for its speech tracking capabilities. MASK has not been systematically tested, so its movement tracking accuracy and practicality for research was still unknown. An error testing and mapping protocol is developed to validate MASK accuracy against established electromagnetic articulography (EMA) speech tracking systems. Data from human speech experiments are also compared. MASK exhibited higher positional error and fluctuation than EMA, and more inconsistent distribution of errors. Error mapping and potential error correction protocols were also developed. MASK spatial and temporal resolutions were found insufficient for precise tracking of small and quick articulatory movements. MASK requires much improvement to reach the capabilities of EMA. Further investigation into numerical instabilities of the position calculation algorithms is encouraged. This project provides the first assessment of MASK, which may advance speech research for future applications.

The purpose of this study was to compare the effects on speech acoustics of a wide variety of speaking instructions that have been used across different studies on clear speech, and to investigate the acoustic and articulatory changes that occur in response to these instructions and in different talking environments. Five young adult females were recorded speaking under different instructions meant to elicit more intelligible speech, and measures of speaking rate, speaking F0 and intensity were found to distinguish instructions to speak "as if to someone with hearing loss" from instructions to speak "clearly" or "slowly", which produced different results from instructions to speak "loudly" or as if in noise. Preliminary acoustic and articulatory data are described for a sixth talker who spoke under a subset of these instructions, and in both a quiet and a noisy talking environment.

The purpose of this study was to compare the effects on speech acoustics of a wide variety of speaking instructions that have been used across different studies on clear speech, and to investigate the acoustic and articulatory changes that occur in response to these instructions and in different talking environments. Five young adult females were recorded speaking under different instructions meant to elicit more intelligible speech, and measures of speaking rate, speaking F0 and intensity were found to distinguish instructions to speak "as if to someone with hearing loss" from instructions to speak "clearly" or "slowly", which produced different results from instructions to speak "loudly" or as if in noise. Preliminary acoustic and articulatory data are described for a sixth talker who spoke under a subset of these instructions, and in both a quiet and a noisy talking environment.

Rupture of the anterior cruciate ligament (ACL) increases anterior-posterior (AP) laxity. The treatment aims to reduce or teach the patient to control this instability. Altered kinematics due to absent ligament function may result in knee arthrosis. This study evaluated the clinical and functional results of reconstructive surgery. Roentgen stereophotogrammetry (RSA) was used to analyse the stabilising effect of knee braces, reconstructive surgery and the kinematics of the knee with and without weight-bearing. The stability of the knees were assessed in 86 patients with ACL injuries before and/or after reconstructive surgery with the RSA technique and with the KT-1000 arthrometer The KT- 1000 (89 N) recorded smaller side to side differences than the RSA set-up without any correlation between the methods. The effect of three different braces on the AP and rotatory laxity was studied on patients with ACL injuries. The ECKO and the modified Lenox Hill reduced the instability with about one third. The SKB had no significant effect. None of the braces decreased the internal rotatory laxity but the Lenox Hill reduced the external rotatory laxity. Thirty-two patients with old ACL tears were treated with surgical reconstruction using the over the top technique (OTT) with or without augmentation. A small reduction in AP laxity was observed at the 6 month follow-up, The AP laxity was almost the same two years after as before surgery. No correlation was observed between the stability and knee function. Fifty-four patients with old unilateral anterior cruciate ligament injuries were randomised either to the over the top (OTT) or the isometric femoral tunnel position (ISO) at ACL reconstructive surgery. Seven of 24 (ISO) and 9 of 25 (OTT) had "normal" laxity two years after surgery. The patients operated with the ISO technique did not have better subjective knee function, muscle strength, functional performance or knee stability than patients operated with the OTT technique. The knee kinematics in patients with chronic unilateral ACL ruptures were examined during active extension in the supine position (13 patients) and during extension and weight-bearing (13 patients). The tibia displaced at an average 1.9 mm more anteriorly and 0.8 mm distally in the injured than in the intact knees during active extension. During extension and weightbearing the tibia was about 2 mm more posteriorly positioned than in the intact knee. The ACL rupture did not affect tibial rotations. Conclusions: The RSA recorded larger side to side differences in ACL injured and reconstructed patients than the KT-1000 arthrometer. Some knee braces are able to reduce AP laxity in ACL injured knees. No correlation was observed after surgery between knee laxity and functional scoring or tests. ACL reconstructions with isometric graft position on the femoral side did not offer any advantages compared to the over the top placement. Altered knee kinematics in the ACL injured knees were observed during knee extension with and without weight-bearing. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1993, härtill 6 uppsatser</p> / digitalisering@umu

Spontaneous vertebral fractures are a large and growing health care problem. Biomechanical factors, specifically, abnormal posture or gait‐related spinal motion may interact with age‐weakened bone to induce altered spinal biomechanics that in turn increase the likelihood of vertebral body fracture. This research takes steps towards the goal of reducing the number of vertebral fractures in two phases: 1) Validation of a noninvasive spinal motion measurement system in cadaver torsos and 2) Application of the measurement system in human subjects. The cadaver study compared vertebral motion at 4 levels (T7,T12,L3,L5) as measured by adhesive skin markers versus motion measured by bone pins implanted into the vertebrae. Cadaver torsos were tested in lateral‐bending, flexion and axialrotation. Mean differences in vertebral body angular motion between skin markers and bone pin markers were <0.5° around the anterior‐posterior and medial‐lateral axes and <0.9° around the superior‐inferior axis. This measurement method was able to accurately quantify vertebral body motion in cadaver torsos thus allowing for application to human subject testing. X‐rays and 3D motion capture were employed to quantify spinal posture and motion parameters during gait in 12 older and 12 younger normal, females. Vertebral motion around 3 axes was measured at 4 levels (T7,T10,T12,L2) using noninvasive retroreflective markers during treadmill gait at 3 speeds (0.5,0.7,0.9m/s). The average angular motion of all gait cycles at each speed was determined for each level. The triplanar ranges of motion and variability of motion were compared as a function of age. Older subjects had 31.7% larger frontal Cobb angles and up to 30.9% and 33.5% smaller ranges of spinal motion in the frontal and sagittal planes. Variability of motion in the sagittal plane was up to 42.9% less in older subjects. Decreased ranges of motion and variability of spinal motion observed in older subjects may imply that vertebral loading in these subjects may not be as uniformly distributed across the vertebrae as in younger subjects. Greater stresses may result from the abnormal motion, thus increasing fracture risk. Confirmation of this hypothesis requires a longitudinal study, but if verified, may lead to the development of inexpensive countermeasures to prevent fractures.

Human locomotion is phenomenon that is extraordinarily complex. It is evident that a complete description of locomotion involves consideration of kinematics, kinetics, and muscle activity of the extremities in all of their various movements. Race walking (RW) is a form of upright locomotion that differs from normal walking and running by its form dictated by the International Amateur Athletics Federation (IAAF). Despite the similarities to both normal walking (NW) and running (RU), RW has not been the subject of equally intensive investigations. This study explores the comprehensive biomechanics of race walking and how it compares to NW and RU. A quantitative approach was used to evaluate kinematic, kinetic and muscle activity variables between race walking and both normal walking and running. A cross-sectional, laboratory design was used on 15 recreationally competitive race walkers to evaluate these variables. Based on the results of this study, RW is an intermediate gait between NW and RU that has characteristics of both gaits, but is still a unique gait in itself. While there are differences between RW and both RU and NW, some of the expected differences between RW and the two gaits did not occur. Significantly greater frontal plane pelvis-trunk joint range of motion and sagittal plane peak hip flexor and extensor moments, hip joint range of motion and rectus femoris muscle activity contribute to the significant differences in both RW and NW, and RW and RU. Significant differences between RW and RU showed that RU requires more contribution from the trunk, pelvis and lower extremities kinematically and kinetically, as well as increased muscle activation, to execute the motion than RW. Conversely, RW requires more contribution from these variables than NW does, but in not as great a capacity as RU compared to RW. In spite of these findings, there were some variables that had no significant differences between RW and RU. This suggests that injuries during RW are similar to those during RU, but may not occur as frequently.

Chronic lateral instability of the ankle (CLI), defined as frequent sprains and recurrent giving way, difficulty in walking and running on uneven surface, is often connected with pain and swollen ankles. It occurs in 10 to 20 percent after acute ankle injuries. Mechanical instability of the talocrural and subtalar joint, peroneal weakness and impaired proprioception has been suggested as etiological factors. Aim. To investigate the natural course in conservatively treated patients with CLI. To assess the mechanical stability in patients with CLI by measuring the three dimensional motions in the talus, the fibula and the calcaneus in relation to the tibia during different testing procedures pre- and postoperatively. To determine if CLI is associated with proprioceptive deficiency. Patients and Methods. This Thesis includes 127 ankles in 78 patients (30 women, 48 men) with CLI. Thirty-seven patients were followed up 20 years after their first contact with the orthopaedic department because of CLI. Forty-six ankles were evaluated radiographically and the result was compared with a gender- and age - matched control-material. The neuromuscular response to a sudden angular displacement of the ankles was studied in 15 ankles in 13 patients using EMG. Thirty-six patients entered a prospective study using roentgen stereophotogrammetric analysis (RSA) in which the ankles were tested at manual adduction, adduction with predetermined torque, with and without external support and at drawer tests (40 N and 160N). Twenty-seven patients were followed five years postoperatively. Result. After 20 years 22 patients, conservatively treated still suffered from instability of the ankle and ten had recurrent giving way symptoms even on plane surface. Six ankles in the patient group and four in the control group displayed osteoarthritic changes Prolonged ipsilateral reaction time (m. per. long, and m. tib. ant.) was found in patients with CLI indicating proprioceptive insufficiency. Increased talar adduction and a tendency toward increased total translation of the talar center was found in ankles with CLI. Concomitant fibular rotations and translations were found but with no conclusive deviation in the ankles with symptoms. The talo-calcaneal adduction reached the same level in the patient and control groups regardless of symptoms. External support (ankle brace) increased the talar stability. The use of predetermined torque and constrained testing procedure did not add information compared with the manual test Twenty-five patients graded the result as excellent or good five years after lateral ligament reconstruction. Talar stability (decreased adduction and translation) was increased two years postoperatively and was improved or remained the same at five years without comprising the range of motion. Conclusion. In more than half the cases symptoms of CLI did not resolve spontaneously. Minor degenerative changes was found after twenty years, but not to a greater extent than in a control group. CLI was associated with proprioceptive insufficiency and talocrural but not subtalar instability. Increased ankle stability can be obtained by the use of an ankle brace and by an anatomical ligament reconstruction. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1994</p> / digitalisering@umu

It is possible to obtain information about various properties of the fuel ions deuterium (D) and tritium (T) in a fusion plasma by measuring the neutron emission from the plasma. Neutrons are produced in fusion reactions between the fuel ions, which means that the intensity and energy spectrum of the emitted neutrons are related to the densities and velocity distributions of these ions. This thesis describes different methods for analyzing data from fusion neutron measurements. The main focus is on neutron spectrometry measurements, using data used collected at the tokamak fusion reactor JET in England. Several neutron spectrometers are installed at JET, including the time-of-flight spectrometer TOFOR and the magnetic proton recoil (MPRu) spectrometer. Part of the work is concerned with the calculation of neutron spectra from given fuel ion distributions. Most fusion reactions of interest – such as the D + T and D + D reactions – have two particles in the final state, but there are also examples where three particles are produced, e.g. in the T + T reaction. Both two- and three-body reactions are considered in this thesis. A method for including the finite Larmor radii of the fuel ions in the spectrum calculation is also developed. This effect was seen to significantly affect the shape of the measured TOFOR spectrum for a plasma scenario utilizing ion cyclotron resonance heating (ICRH) in combination with neutral beam injection (NBI). Using the capability to calculate neutron spectra, it is possible to set up different parametric models of the neutron emission for various plasma scenarios. In this thesis, such models are used to estimate the fuel ion density in NBI heated plasmas and the fast D distribution in plasmas with ICRH.

This thesis presents a geometric approach to studying kinematics, dynamics and controls of open-chain multi-body systems with non-zero momentum and multi-degree-of-freedom joints subject to holonomic and nonholonomic constraints. Some examples of such systems appear in space robotics, where mobile and free-base manipulators are developed. The proposed approach introduces a unified framework for considering holonomic and nonholonomic, multi-degree-of-freedom joints through: (i) generalization of the product of exponentials formula for kinematics, and (ii) aggregation of the dynamical reduction theories, using differential geometry. Further, this framework paves the ground for the input-output linearization and controller design for concurrent trajectory tracking of base-manipulator(s). In terms of kinematics, displacement subgroups are introduced, whose relative configuration manifolds are Lie groups and they are parametrized using the exponential map. Consequently, the product of exponentials formula for forward and differential kinematics is generalized to include multi-degree-of-freedom joints and nonholonomic constraints in open-chain multi-body systems. As for dynamics, it is observed that the action of the relative configuration manifold corresponding to the first joint of an open-chain multi-body system leaves Hamilton's equation invariant. Using the symplectic reduction theorem, the dynamical equations of such systems with constant momentum (not necessarily zero) are formulated in the reduced phase space, which present the system dynamics based on the internal parameters of the system. In the nonholonomic case, a three-step reduction process is presented for nonholonomic Hamiltonian mechanical systems. The Chaplygin reduction theorem eliminates the nonholonomic constraints in the first step, and an almost symplectic reduction procedure in the unconstrained phase space further reduces the dynamical equations. Consequently, the proposed approach is used to reduce the dynamical equations of nonholonomic open-chain multi-body systems. Regarding the controls, it is shown that a generic free-base, holonomic or nonholonomic open-chain multi-body system is input-output linearizable in the reduced phase space. As a result, a feed-forward servo control law is proposed to concurrently control the base and the extremities of such systems. It is shown that the closed-loop system is exponentially stable, using a proper Lyapunov function. In each chapter of the thesis, the developed concepts are illustrated through various case studies.