A Method for Attitude Control Based on a Mathematical Model for an Inverted Pendulum-Type Mobile Robot

A method for attitude control based on a mathematical model for an inverted pendulum-type mobile robot was proposed. The inverted pendulum-type mobile robot was designed and the mathematical modeling was conducted. The parameters of the mobile robot were estimated and the state-space model of mobile robot was obtained by the substitution of the estimated parameters into the mathematical model. The transfer function of the mobile robot is applied to generate the root-locus diagram used for the estimation of the gains of the PID controller. The attitude control method including a PID controller, non-linear elements, and integral saturation prevention was designed and simulated. The experiment was conducted by applying the method to the mobile robot. In the attitude control experiment, the performance of attitude recovery from ±12° tilted initial state with a settling time of 0.98s and a percent overshoot of 40.1% was obtained. Furthermore, the attitude maintaining robustness against disturbance was verified

Minimum Distance Testing and Top Income Shares in Korea

We study Kolmogorov-Smirnov goodness of fit tests for evaluating distributional hypotheses where unknown parameters need to be fitted. Following work of Pollard (1979), our approach uses a Cramér-von Mises minimum distance estimator for parameter estimation. The asymptotic null distribution of the resulting test statistic is represented by invariance principle arguments as a functional of a Brownian bridge in a simple regression format for which asymptotic critical values are readily delivered by simulations. Asymptotic power is examined under fixed and local alternatives and finite sample performance of the test is evaluated in simulations. The test is applied to measure top income shares using Korean income tax return data over 2007 to 2012. When the data relate to the upper 0.1% or higher tail of the income distribution, the conventional assumption of a Pareto tail distribution cannot be rejected. But the Pareto tail hypothesis is rejected for the top 1.0% or 0.5% incomes at the 5% significance level

The Effects of Air Pollution on Mortality in South Korea

AbstractIt is well known that air pollution has the negative effect on human health. This study is dealt with the relationship between air pollutant level and standardized mortality between 2005 and 2013 in Korea. The standardized mortality are collected by the 251 administrative districts using KOSIS (Korean Statistical Information Service) and the air pollutant data collected from air pollutant monitoring sites. The statistical interpolation technique is adapted to solve the problem of spatial misalignment between air pollutant and administrative districts. In addition, SaTScan is used to detecting the high relatively risk area based on spatial and temporal characteristics. It can help determining other external factors to mortality

Use of signal sequences as an in situ removable sequence element to stimulate protein synthesis in cell-free extracts

This study developed a method to boost the expression of recombinant proteins in a cell-free protein synthesis system without leaving additional amino acid residues. It was found that the nucleotide sequences of the signal peptides serve as an efficient downstream box to stimulate protein synthesis when they were fused upstream of the target genes. The extent of stimulation was critically affected by the identity of the second codons of the signal sequences. Moreover, the yield of the synthesized protein was enhanced by as much as 10 times in the presence of an optimal second codon. The signal peptides were in situ cleaved and the target proteins were produced in their native sizes by carrying out the cell-free synthesis reactions in the presence of Triton X-100, most likely through the activation of signal peptidase in the S30 extract. The amplification of the template DNA and the addition of the signal sequences were accomplished by PCR. Hence, elevated levels of recombinant proteins were generated within several hours

Coexisting multiple dynamic states generated by magnetic field in Bi-2212 stacked Josephson junctions

Josephson vortices in naturally stacked Bi-2212 tunneling junctions display rich dynamic behavior that derives from the coexistence of three basic states: static Josephson vortex lattice, coherently moving lattice, and incoherent quasiparticle tunneling state. Rich structure of hysteretic branches observed in the current-voltage characteristics can be understood as combinatorial combinations of these three states which are realized in different junctions and evolve separately with magnetic field and bias current. In particular, the multiple Josephson-vortex-flow branches at low bias currents arise from the individual depinning of Josephson vortex rows in each junction.Comment: Submitted to Europhysics Letter

Value of Paraspinal Electromyography in the Evaluation of Thoracic Myelopathy

The authors have performed paraspinal needle EMG studies in twenty five patients with thoracic myelopathy. They were divided into demonstrable thoracic lesions and non-demonstrable thoracic lesions by neuroimaging studies resulting in 12 cases of the former and 13 cases of the latter. There were abnormal paraspinal EMG findings in 83% with demonstrable thoracic lesions. All five patients with thoracic disc diseases revealed abnormalities which indicated subsequent involvement of ventral roots by compressive lesions. In non-demonstrable thoracic lesions, the authors could demonstrate abnormal paraspinal EMGs in a relatively high percentage (62.5%) of preseumed and still occult thoracc myelopathy, but not in all four patients with demyelinating disease. Therefore it is concluded that paraspinal EMG studies are valuable in those patients wih thoracic myelopathy as a method of predicting he presumed nature of their causes and indicating the level of anticipated myelography or spinal CT. However, it was impossible to differentiate among patients with malignancy, those with thoracic disc diseases and those with unknown thoracic myelopathy by the paraspinal EMG studies

Thermal plasma flow and equivalent circuit analyses on the electrical coupling of a DC-RF hybrid plasma torch

Numerical analyses on the electrical coupling of a DC-RF (direct current – radio frequency) hybrid plasma torch are conducted on the basis of magneto-hydrodynamic flow and equivalent circuit models to find the dependency of coupling efficiency on RF frequency and confinement tube radius. Computations are also carried out for the inductively coupled RF plasma torch to make a comparison between their calculated results. Numerical results reveal that the electrical coupling efficiencies of the RF and DC-RF hybrid plasma torches have a similar dependency on RF frequency with an almost constant difference of slightly higher efficiencies for the hybrid plasma, due to the relatively linear frequency dependency of equivalent circuit parameters as well as the resultant radially expanded DC-RF hybrid plasma toward the confinement tube wall compared with the RF plasma. But it is found that the reduction in the confinement tube radius less than some critical value, for instance 22 mm in this numerical work, possibly causes the coupling efficiency of the hybrid plasma to drastically deteriorate compared with that of the RF plasma. Such poor efficiency of the hybrid torch with relatively small radius is attributed to a significant diminution of the high temperature region upstream between the DC torch exit and the first induction coil segment, which means that the reduced tube radius may lead to an ineffective superposition of DC arc jet and RF plasma. As a result of the reduced high temperature region, the magnetic flux linkage is decreased for the smaller confinement tube, which leads to a drastic decrease in the electrical coupling. As the confinement tube radius becomes smaller, the re-circulation eddies under the DC torch are almost destroyed by a DC arc jet and a stagnation region formed is contracted to the central region. This contracted stagnation region prohibits the convection heat transfer by re-circulation of sheath gas flow from the coil zone to the upper part of the confinement tube, which ultimately results in a significant diminution of the high temperature region in the upstream. The present numerical analyses indicate that a special focus need to be brought into the influences of the DC arc jet on the electrical and thermal flow characteristics of the DC-RF hybrid plasma in determining the torch dimensions for effective conversion of RF power into plasma