Seismic Hazard Estimation Based on Non-Poisson Earthquake Occurrences

A non-Poisson earthquake occurrence model for seismic hazard estimation is developed to account for the periodicity and the nonstationarity in seismic activities. The model consists of a renewal process model for major fault systems and a nonstationary Poisson-type model for secondary seismic sources, the latter being dominated by the former. The model is identified on the basis of the historical earthquake data for the Kinki District in the western part of Japan, containing the Kyoto-Osaka-Kobe metropolitan area. A simulation model for seismic hazard estimations (ground acceleration and velocity are dealt with) is then developed by combining the non-Poisson earthquake occurrence model and probabilistic attenuation rules. On the basis of the results of the simulation, the significance of the periodicity and the nonstationarity of seismic activities in assessing the seismic risk is discussed

NEW RESEARCH APPROACHES ARE UNRAVELLING THE MYSTERY OF PROPULSIVE MECHANISMS IN SWIMMING

Various explanations regarding how swimmers generate propulsion have been proffered during the last half century, Investigations have been limited by the current technical 'state of the art'. The main limitations have related to the difficulty of directly measuring propulsive and resistive forces and in observing the behaviour of the fluid. The purpose of this presentation is to provide an historical account of how developing methods of analysis are enabling us to unravel the mystery of propulsion in swimming

Estimating Hydrodynamic Forces Acting on the Hand during Sculling in Synchronized Swimming

The characteristics of the hydrodynamic farces acting on the hand at different loads during sculling in synchronized swimming was estimated using a pressure distribution measuring method. One cycle of flat scull in a back layout position and support scull in a vertical position for one female national-level synchronized swimmer were analyzed. Results showed, at small loads in the flat scull, larger hydrodynamic force was observed during out-scull. As load increased, the hydrodynamic force increased during in-scull, and the values were observed to equalize between in-scull and out-scull. At all loads in the support scull, the larger value was observed during in-scull. It was apparent that in both sculls, the hydrodynamic force increased as the load increased, and the pressure on the dorsum of the hand decreased when large hydrodynamic force was generated

A SIMULATION OF STROKE EFFICIENCY DURING FRONT CRAWL BY USING THE SWIMMING HUMAN SIMULATION MODEL

Nakashima et al. (2005) have developed a swimming human simulation model (SWUM) considering rigid body dynamics and unsteady fluid for the whole body. By using this model, it comes to be able to estimate the mechanical efficiency during human swimming which has been difficult to obtain its actual measurement value. The purpose of this study was to estimate the mechanical efficiency during front crawl in varied swimming velocity. If this estimation is considered reasonable and proper, the SWUM may become a useful tool to create a new efficient stroke movement in the water

A METHOD OF IMPROVING THE MEASUREMENT OF KINEMATIC PARAMETERS ABOVE AND UNDER WATER IN SWIMMING START

The objectives of this study were to develop an improved method of measuring kinematic parameters of a swimmer at the start of a race from water entry through the initial glide in a seamless manner and to consider deceleration factors with reference to changes in the swimmer’s kinematic parameters during the start. Ten elite collegiate male swimmers participated in this study. To obtain accurate displacements of each reference point on a swimmer while avoiding interference from bubbles, waterproofed, super-luminosity LED markers were used. Additionally, a metallic frame (3 m × 2 m) and a nylon belt (6.1 m long with marks at intervals of 0.5 m) were used as calibration control points. Participants were asked to start from a starting block three times with their maximum effort and maintain a streamlined position without any kicking after water entry until they reached the 10-m point. The mean calibration error was 0.0046 m in the horizontal direction and 0.0047 m in the vertical direction across the measurement span (11 m × 6 m). This improved method enabled us to measure successive changes in the velocity and acceleration of the centre of mass both above water and following water entry

Success management in information systems projects

Programa doutoral em Tecnologias e Sistemas de InformaçãoFundação para a Ciência e a Tecnologia - UI/BD/150853/202

PREDICTION OF FLUID FORCES ACTING ON A HAND MODEL IN UNSTEADY FLOW CONDITIONS

A method to predict resultant ftuid forces acting on the hands in unsteady conditions was developed for kinematic and for pressure data for a hand model. The hand model was rotated in the flume. Regression analysis was used to find best-fit equations to predict the resultant fluid forces acting on the hand model. The best-fit equations for pressure and kinematic data were built, and the equation for pressure data was more accurate. The new pressure method predicted more accurately the fluid forces acting on the hand model than the kinematic method and does not require orientation angles of the hand. The mean RMS error in prediction from pressure was 4.2 N compared to 6.7 N from kinematic data (p < 0.01)

KINETIC ANALYSIS OF START MOTION ON STARTING BLOCK IN COMPETITIVE SWIMMING

The aim of this study was to investigate kinetic features of start motion with use of an instrumented starting block. This is the first study that quantified joint torques of the whole body during start motion. Six male swimmers dived from the instrumented starting block, which contains force plates and sensors. Four high-speed cameras were used to obtain kinematics data of the swimmers. Inverse dynamics calculation was carried out with use of the kinetics and kinematics data. The results showed that 1) the large pulling up forces exerted by both hands were generated by extension toques of the shoulder joints, 2) the rear side lower limb joints exerted large extension torque to obtain horizontal reaction force, and 3) the knee joint of the front side lower limb exerted large flexion torque to maintain the large vertical reaction force until 60% normalized start motion time

HYDRODYNAMIC RE-EXAMINATION OF UNDERWATER NON-PROPULSIVE PHASE IN FRONT CRAWL

The purpose of this study was to re-examination of the hand propulsive force (FP) during the entry and catch (EC) phase in a stroke of front crawl. The EC phase was defined as non-propulsive phase (Collet et al., 2000), which is until a hand starts moving backwards after it enters the water and moves forward. The other phases in the stroke was defined as propulsive phase. Twelve male swimmers performed a 20-m front crawl with maximal effort. For estimatinng the FP, six pressure sensors were attched on their right hand and trials were recorded by three-dimentional motion capture system. We calculated %EC that was the ratio of the mean FP in the EC phase to the mean FP in the propulsive phase. As a result, the mean FP in the EC phase was 22.4 ± 12.9 N and the %EC was 29.1%. Therefore, it was considered the EC phase is propulsive phase even though the hand moves forward