Field and Analytical Studies of the First Folded Plate Girder Bridge

Integral abutment bridges are very common for short span bridges in the United State due to their less construction and maintenance cost and generally good performance. This thesis studies the first integral abutment bridge using Folded Plate Girder (FPG) Bridge System. The bridge is instrumented with a variety of gauges to capture the behavior of the bridge, and a total of two year and one month [11/2011~12/2013] of data are collected and long-term data monitoring is performed. Live load test and long term temperature effect on the bridge are studied using finite element modeling and compared with actual field data. Girder strain/stress at mid-span and quarter-span and abutment rotations were investigated. From the result, first the bridge was found to show good performance. Shear lag effect was found to be happening at the bottom flange-to-web junction of the steel girder when subjected to concentrated loading. Thermal gradient was found to be significant on the girder strain and abutment rotations

Distributed Time-Sensitive Task Selection in Mobile Crowdsensing

With the rich set of embedded sensors installed in smartphones and the large number of mobile users, we witness the emergence of many innovative commercial mobile crowdsensing applications that combine the power of mobile technology with crowdsourcing to deliver time-sensitive and location-dependent information to their customers. Motivated by these real-world applications, we consider the task selection problem for heterogeneous users with different initial locations, movement costs, movement speeds, and reputation levels. Computing the social surplus maximization task allocation turns out to be an NP-hard problem. Hence we focus on the distributed case, and propose an asynchronous and distributed task selection (ADTS) algorithm to help the users plan their task selections on their own. We prove the convergence of the algorithm, and further characterize the computation time for users' updates in the algorithm. Simulation results suggest that the ADTS scheme achieves the highest Jain's fairness index and coverage comparing with several benchmark algorithms, while yielding similar user payoff to a greedy centralized benchmark. Finally, we illustrate how mobile users coordinate under the ADTS scheme based on some practical movement time data derived from Google Maps

LOWER EXTREMITY JOINT KINETICS DURING LANDING OF A DROP JUMP FROM DIFFERENT HEIGHTS AND LANDING SURFACES

This study aimed to investigate the biomechanical effect of the lower extremity joints from a vertical fall of 30 cm and 60 cm to a soft mat and a stiff floor respectively. Result shows, from either height, the joint forces and peak joint moments decrease significantly, while the joint angles changes to a greater degree when landing on a soft mat and it needs more time from initial contact till the action stops. 'Each joint moment is effect of external moment and internal muscle moment together. The correct landing technique is that moments of all joints reduce simultaneously, Le. the contraction and passive extension of muscles should be controlled in sequence and magnitude. The highest muscle moment on contact landing is observed at hip joint on 'both landing conditions and the muscles of the knee and ankle joints guided by the hip muscles assist each other

ESTABLISHMENT OF NATIONAL STANDARD FOR INERTIAL PARAMETERS OF CHINESE ADULTS

Utilizing the database of human body measurement of Chinese adults, 128 regression equations of inertial parameters of adult human body segments were established in the study on the base of research on inertial parameters of young human body segments using the CT method. These equations includes: the binary and plural regression equations that calculate segmental mass and center of mass of adult male or a female; the binary and plural regression equations that calculate segmental and the whole body inertial moments of adult male or female. A measuring system consisting of a three-wire pendulum instrument and center of gravity plank is also devised in the study. After measuring the selected Chinese adults (80 males and 40 females), the regression equations of inertial parameters of Chinese adults are verified. A national standard was subsequently established