Adaptive Accumulation of Plantar Pressure for Ambulatory Activity Recognition and Pedestrian Identification.

In this paper, we propose a novel method for ambulatory activity recognition and pedestrian identification based on temporally adaptive weighting accumulation-based features extracted from categorical plantar pressure. The method relies on three pressure-related features, which are calculated by accumulating the pressure of the standing foot in each step over three different temporal weighting forms. In addition, we consider a feature reflecting the pressure variation. These four features characterize the standing posture in a step by differently weighting step pressure data over time. We use these features to analyze the standing foot during walking and then recognize ambulatory activities and identify pedestrians based on multilayer multiclass support vector machine classifiers. Experimental results show that the proposed method achieves 97% accuracy for the two tasks when analyzing eight consecutive steps. For faster processing, the method reaches 89.9% and 91.3% accuracy for ambulatory activity recognition and pedestrian identification considering two consecutive steps, respectively, whereas the accuracy drops to 83.3% and 82.3% when considering one step for the respective tasks. Comparative results demonstrated the high performance of the proposed method regarding accuracy and temporal sensitivity.

Gas-Permeable Inorganic Shell Improves the Coking Stability and Electrochemical Reactivity of Pt toward Methane Oxidation.

Solid oxide fuel cells produce electricity directly by oxidizing methane, which is the most attractive natural gas fuel, and metal nanocatalysts are a promising means of overcoming the poor catalytic activity of conventional ceramic electrodes. However, the lack of thermal and chemical stability of nanocatalysts is a major bottleneck in the effort to ensure the lifetime of metal-decorated electrodes for methane oxidation. Here, for the first time, this issue is addressed by encapsulating metal nanoparticles with gas-permeable inorganic shells. Pt particles approximately 10 nm in size are dispersed on the surface of a porous La0.75Sr0.25Cr0.5Mn0.5O3 (LSCM) electrode via wet infiltration and are then coated with an ultrathin Al2O3 layer via atomic layer deposition. The Al2O3 overcoat, despite being an insulator, significantly enhances the immunity to carbon coking and provides high activity for the electrochemical oxidation of methane, thereby reducing the reaction impedance of the Pt-decorated electrode by more than 2 orders of magnitude and making the electrode activity of the Pt-decorated sample at 650 °C comparable with those reported at 800 °C for pristine LSCM electrodes. These observations provide a new perspective on strategies to lower the operation temperature, which has long been a challenge related to hydrocarbon-fueled solid oxide fuel cells.

Development of deformable moving lung phantom to simulate respiratory motion in radiotherapy.

Radiation treatment requires high accuracy to protect healthy organs and destroy the tumor. However, tumors located near the diaphragm constantly move during treatment. Respiration-gated radiotherapy has significant potential for the improvement of the irradiation of tumor sites affected by respiratory motion, such as lung and liver tumors. To measure and minimize the effects of respiratory motion, a realistic deformable phantom is required for use as a gold standard. The purpose of this study was to develop and study the characteristics of a deformable moving lung (DML) phantom, such as simulation, tissue equivalence, and rate of deformation. The rate of change of the lung volume, target deformation, and respiratory signals were measured in this study; they were accurately measured using a realistic deformable phantom. The measured volume difference was 31%, which closely corresponds to the average difference in human respiration, and the target movement was - 30 to + 32mm. The measured signals accurately described human respiratory signals. This DML phantom would be useful for the estimation of deformable image registration and in respiration-gated radiotherapy. This study shows that the developed DML phantom can exactly simulate the patient׳s respiratory signal and it acts as a deformable 4-dimensional simulation of a patient׳s lung with sufficient volume change.

Surface engineering of nanoporous substrate for solid oxide fuel cells with atomic layer-deposited electrolyte.

Solid oxide fuel cells with atomic layer-deposited thin film electrolytes supported on anodic aluminum oxide (AAO) are electrochemically characterized with varying thickness of bottom electrode catalyst (BEC); BECs which are 0.5 and 4 times thicker than the size of AAO pores are tested. The thicker BEC ensures far more active mass transport on the BEC side and resultantly the thicker BEC cell generates ≈11 times higher peak power density than the thinner BEC cell at 500 °C.

Plasma-enhanced atomic layer deposition of nanoscale yttria-stabilized zirconia electrolyte for solid oxide fuel cells with porous substrate.

Nanoscale yttria-stabilized zirconia (YSZ) electrolyte film was deposited by plasma-enhanced atomic layer deposition (PEALD) on a porous anodic aluminum oxide supporting substrate for solid oxide fuel cells. The minimum thickness of PEALD-YSZ electrolyte required for a consistently high open circuit voltage of 1.17 V at 500 °C is 70 nm, which is much thinner than the reported thickness of 180 nm using nonplasmatic ALD and is also the thinnest attainable value reported in the literatures on a porous supporting substrate. By further reducing the electrolyte thickness, the grain size reduction resulted in high surface grain boundary density at the cathode/electrolyte interface.

Intermediate-Temperature Solid-Oxide Fuel Cells with a Gadolinium-Doped Ceria Anodic Functional Layer Deposited via Radio-Frequency Sputtering.

We investigated the effects of the insertion of a gadolinium-doped ceria (GDC) anodic functional layer (AFL) on the electrochemical performance of intermediate-temperature solid-oxide fuel cells (SOFCs). Fully stabilized yttria-stabilized zirconia (YSZ) was used as an oxygen-ion-conducting and support material. Nickel-Samaria-doped ceriathin film was used as an anode material, while screen-printed lanthanum strontium magnetite served as a cathode material. In order to enhance the interfacial reaction on the anode side, a GDC-AFL with a thickness of about 140 nm, deposited via radio-frequency sputtering, was inserted into the anode-electrolyte interface. SOFCs with and without a GDC-AFL were electrochemically characterized. In an intermediate temperature range of about 700 - 800 degrees C, the application of the GDC-AFL led to an increase in the peak power density of approximately 16%.

Fabrication of low-temperature solid oxide fuel cells with a nanothin protective layer by atomic layer deposition.

Anode aluminum oxide-supported thin-film fuel cells having a sub-500-nm-thick bilayered electrolyte comprising a gadolinium-doped ceria (GDC) layer and an yttria-stabilized zirconia (YSZ) layer were fabricated and electrochemically characterized in order to investigate the effect of the YSZ protective layer. The highly dense and thin YSZ layer acted as a blockage against electron and oxygen permeation between the anode and GDC electrolyte. Dense GDC and YSZ thin films were fabricated using radio frequency sputtering and atomic layer deposition techniques, respectively. The resulting bilayered thin-film fuel cell generated a significantly higher open circuit voltage of approximately 1.07 V compared with a thin-film fuel cell with a single-layered GDC electrolyte (approximately 0.3 V).

Boosted reaction on two-step tuberculin skin test among military personnel in South Korea, a setting with an intermediate burden of tuberculosis and routine bacille Calmette-Guerin vaccination.

This study was performed to estimate the rate of boosted reaction in the two-step tuberculin skin test (TST) and to evaluate the associated factors among military personnel of South Korea, which has an intermediate burden of tuberculosis (TB) and a routine bacille Calmette-Guerin (BCG) vaccination policy. Two-step TST was performed on 264 military personnel who did not have a history of close contact to TB. Subjects with a negative reaction to the first test of <10 mm had a second TST applied 1 week later on the other forearm. A positive result (> or =10 mm) on the initial TST was observed in 126 (48%) of the subjects. A boosted reaction on the second TST developed in 32 (23%) of the 124 subjects with a negative initial TST. In multiple logistic regression analysis, the size of the initial TST reaction was the only factor associated with a boosted reaction on the second TST. The high rate of boosted reaction among healthy adults in South Korea suggests that two-step TST should be performed to assess the baseline TST reactivity in settings with an intermediate burden of TB and routine BCG vaccination policy, especially among subjects with an initial TST reaction that is > or =5 mm.