Topology-Guided Path Integral Approach for Stochastic Optimal Control in Cluttered Environment

This paper addresses planning and control of robot motion under uncertainty that is formulated as a continuous-time, continuous-space stochastic optimal control problem, by developing a topology-guided path integral control method. The path integral control framework, which forms the backbone of the proposed method, re-writes the Hamilton-Jacobi-Bellman equation as a statistical inference problem; the resulting inference problem is solved by a sampling procedure that computes the distribution of controlled trajectories around the trajectory by the passive dynamics. For motion control of robots in a highly cluttered environment, however, this sampling can easily be trapped in a local minimum unless the sample size is very large, since the global optimality of local minima depends on the degree of uncertainty. Thus, a homology-embedded sampling-based planner that identifies many (potentially) local-minimum trajectories in different homology classes is developed to aid the sampling process. In combination with a receding-horizon fashion of the optimal control the proposed method produces a dynamically feasible and collision-free motion plans without being trapped in a local minimum. Numerical examples on a synthetic toy problem and on quadrotor control in a complex obstacle field demonstrate the validity of the proposed method.Comment: arXiv admin note: text overlap with arXiv:1510.0534

DNA Vaccine Expressing Mature Dengue Virus-Like Particles and Serological Tests to Distinguish Dengue and Zika.

M.S. Thesis. University of Hawaiʻi at Mānoa 2017

An N-bit digitally variable ultra wideband pulse generator for GPR and UWB applications

This paper presents a low-cost Ultra Wideband (UWB) pulse generator that can vary the pulse duration digitally by using a Step Recovery Diode (SRD), microstrip transmission lines and PIN diodes. First, a sharp edge is generated by using a SRD circuitry. Then a pulse is formed from the sharp edge through the use of transmission lines and the PIN diodes. Based on the number of transmission lines (N), the duration of the pulse can be varied in steps. The UWB pulse generator circuits are implemented on an FR-4 substrate using microstrip line technology and UWB pulses with durations of 550 to 2400 psec are measured. N2 Ke

A Real-time Filtering Method of Positioning Data with Moving Window Mechanism

Nowadays, advanced mobile devices can obtain current position with the help of positioning data systems such as GPS, GLONASS, Galileo, and so on. However, positioning data sets usually have erroneous data for various reasons, mainly due to the environmental issues as well as inherent systematical issues. While doing research related to positioning data sets, authors experienced quite a large number of erroneous positioning data using Apple iPhone or Samsung Galaxy devices, and thus need to filter evident errors. In this paper, we will suggest relatively simple, but efficient filtering method based on statistical approach. From the user’s mobile positioning data in a form of < latitude; longitude; time > obtained by mobile devices, we can calculate user’s speed and acceleration. From the idea of sliding window (moving window), we can calculate statistical parameters from speed and acceleration of user position data and thus filtering can be made with controllable parameters. We expect that the simplicity of our algorithm can be applied on portable mobile device with low computation power. For the possible enhancement of our method, we will focus on the construction of more precise window for better filtering. A backtracking interpolation was added in order to replace erroneous data with proper estimations in order to have more precise estimation of moving window. We also proposed this filtering algorithm with interpolation as a basis of future investigation in the section of conclusion and future research. Keywords: Human Mobility, Error Filtering, Positioning Data, Moving Window, Sliding Windo