This paper summarizes how Team KAIST prepared for the DARPA Robotics Challenge (DRC) Finals, especially in terms of the robot system and control strategy. To imitate the Fukushima nuclear disaster ...situation, the DRC performed eight tasks and degraded communication conditions. This competition demanded various robotic technologies, such as manipulation, mobility, telemetry, autonomy, and localization. Their systematic integration and the overall system robustness were also important issues in completing the challenge. In this sense, this paper presents a hardware and software system for the DRC‐HUBO+, a humanoid robot that was used for the DRC; it also presents control methods, such as inverse kinematics, compliance control, a walking algorithm, and a vision algorithm, all of which were implemented to accomplish the tasks. The strategies and operations for each task are briefly explained with vision algorithms. This paper summarizes what we learned from the DRC before the conclusion. In the competition, 25 international teams participated with their various robot platforms. We competed in this challenge using the DRC‐HUBO+ and won first place in the competition.
Scope
Long‐term feeding of a high‐fat diet (HFD) causes gastrointestinal inflammation and gut microbiota disturbance, leading to the increased occurrence of obesity and anxiety. In the present study, ...the effects of heat‐labile Lactobacillus sakei OK67, tyndallized OK67 (tOK67), and heat‐stable Lactobacillus sakei PK16 on HFD‐induced obesity and anxiety in mice are examined.
Methods and results
Obesity is induced in mice by feeding with HFD. Oral administration of live OK67, tOK67, or PK16 reduces HFD‐induced body and liver weights and blood triglyceride, total cholesterol, corticosterone, and lipopolysaccharide levels. These treatments also suppress HFD‐induced NF‐κB activation and increased HFD‐suppressed AMP‐activated protein kinase (AMPK) activation and SIRT‐1 expression in the liver. OK67 or PK16 treatment alleviates HFD‐induced anxiety‐like behaviors and increases BDNF expression and NF‐κB activation in the hippocampus. Moreover, OK67 or PK16 treatment suppresses HFD‐induced colitis and suppresses the Proteobacteria population and fecal lipopolysaccharide levels in mice. OK67 or PK16 treatment inhibits NF‐κB activation and induced AMPK activation and SIRT‐1 expression in lipopolysaccharide‐stimulated Caco‐2 cells. Overall, the antiobesity and anxiolytic effects of live OK67 are more potent than those of tOK67.
Conclusion
Lactobacillus sakei can alleviate HFD‐induced obesity, colitis, and anxiety by regulating gut microbiota‐mediated AMPK and NF‐κB activation and SIRT‐1 expression.
Long‐term feeding of a high‐fat diet (HFD) causes obesity, colitis, and anxiety. In the present study, it has been found that Lactobacillus sakei OK67 and PK16 attenuate HFD‐induced obesity, liver steatosis, colitis, and anxiety‐like behaviors in mice by inducing AMPK activation and SIRT1 expression and inhibiting gut‐microbiota‐mediated NF‐κB activation.
Recent research on humanoid robot actuators has shown that the use of series elastic actuators (SEAs) is necessary for accurate and robust torque control. Among the numerous implementations of an ...SEA, using a spring as an elastomer is considered to be the most suitable. However, a major disadvantage of this method in terms of torque control is the hysteresis of the elastomer. Although various hysteresis modeling methods have been studied to resolve the hysteresis problem of an elastomer, they are not sufficiently accurate to perform torque control. Therefore, we propose a hysteresis model and compensation method to estimate torque based on deformation for the hysteresis of an elastomer SEA to resolve the problems encountered in previous studies. Torque control is evaluated with the proposed hysteresis compensation method. Torque measurements obtained using the proposed hysteresis model improve the maximum error by up to 10% compared with that of Hooke's law, which has a maximum error of 25%. Torque control of an elastomer SEA can be performed with improved accuracy by using the proposed hysteresis model and compensation method.
This study investigated the effect of local structural coupling between the buffer and the superconducting layers on the superconductivity of a GdBa2Cu3O7-x (GdBCO)/La0.7Sr0.3MnO3 (LSMO) bilayer. ...Epitaxial bilayers consisting of GdBCO with varying thicknesses (100, 300, and 500 nm), with and without LSMO (100 nm), were fabricated on a (001) SrTiO3 substrate. To investigate the local structural distortion within the GdBCO/LSMO system, the temperature-dependent extended X-ray absorption fine structure (EXAFS) spectra were measured at the Mn- and Cu–K absorption edges. The EXAFS analyses revealed local structural non-uniformity, which manifested as anomalies in the temperature dependence of both the Mn–O and Cu–O bond distributions. A strong correlation exists between the local structural distortion of the Mn–O bond and the degree of lattice instability in the CuO2 plane, which exhibits a strong thickness dependence. The inter-atomic potential of oxygen oscillations with an anharmonic approximation was adopted to interpret the structural anomalies. As a result, a double-well potential was obtained near Tc, owing to the occurrence of longer Cu–O bonds in the CuO2 plane. The difference in the degree of structural anomalies depending on the GdBCO thickness manifested as a difference in the distance between the two wells, which closely correlates with the appearance of a superconducting state. These experimental results demonstrate the role of local lattice fluctuations in the superconducting mechanism of the GdBCO/LSMO bilayer.
•GC analysis (<10 min) of volatile organics at sub-ppb levels was done•Electronic pressure control facilitated use of compressed ambient air as carrier gas•Temperature programming was achieved by the ...at-column heater and insulation module•Photoionization detector exhibited a fast response (<90 ms)•Sensitivity was increased 100-fold using a carbon nanotube sponge preconcentrator
We describe the design and performance evaluation of a portable gas chromatograph suitable for the analysis of volatile organic and odorous compounds at trace levels. The system comprises a carbon nanotube sponge preconcentrator, an electronic pressure control (EPC) unit, a temperature-programmable column module, and a fast-response photoionization detector. A built-in tablet computer controls instrumental parameters and chromatogram display functions. The compact GC with dimensions of 35 cm (l) × 26 cm (w) × 15 cm (h) is self-contained, weighing less than 5 kg without a battery pack, and uses no auxiliary compressed gases. Our design has three main advantages over conventional portable GCs: recharging configuration of ambient air as the carrier gas using a miniature diaphragm pump, precise control of column flow by the built-in canister and EPC system, and rapid thermal desorption of the preconcentrator facilitated by intrinsic resistivity of the carbon nanotube sponge. A 30 m, 0.28 mm I.D. capillary column operated at a head pressure of 14 psi provided a peak capacity of 55 for a 10 min isothermal analysis. The temperature-programmability feature could decrease the analysis time of less than 5 min for vapor mixture of benzene, toluene, ethylbenzene, and o-xylene. More than a 100-fold increase in sensitivity by preconcentrating a sample adsorption volume of 90 mL resulted in improved detection limits of 0.13 (benzene), 0.20 (toluene), 0.23 (ethylbenzene), and 0.28 (o-xylene) ppb (v/v). Our instrument displayed good stability and reproducibility of retention times (< 0.14% RSD) and intensities (< 4.5% RSD) for continuous measurements using the preconcentrator over 10 h. Thus, continuous and on-site determinations of trace volatile organic compounds in air samples with this instrument appear feasible.
The catalytic oxidation of volatile organic compounds such as benzene, toluene, ethylbenzene, and o-xylene (BTEX) over novel Pt/carbon nanotube (CNT) catalysts fabricated by a molecular-level mixing ...method was investigated at temperatures ranging from 40 to 150 degree C. The Pt/CNT interface was probed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray spectroscopy (EDS) to elucidate the binding nature of the Pt nanoparticle-CNT surface. The breakthrough curves for multi-component mixtures show displacement effects, in which adsorbates exhibit interaction forces that are sufficiently to displace weakly bounded substances during adsorption. Catalytic oxidation was conducted using a BTEX concentration ranging from 100 to 500ppmv in air at volume hour space velocities (VHSVs) of approximately 7.5104 h-1-3.4105 h-1. The light-off curves were very steep, and complete oxidation was realized at temperatures as low as 115 degree C with 30wt% Pt/CNT, well below the temperatures required using previously studied Pt-based catalysts. The oxidation activity was presumably promoted because of the higher surface BTEX concentration afforded by the adsorption capability of multiwalled carbon nanotubes. The catalyst was characterized by its unique hydrophobic property, which facilitated the conversion of BTEX with high activity at relatively low temperatures and was unaffected by moisture in the system.
Navigation in the absence of initial environmental information is a situation in which a robot is faced with the difficulty of traversing an unknown area for exploration with obtaining the ...environmental information simultaneously. Therefore, to complete and optimize the exploration efficiently, the robot needs an autonomous path‐planning algorithm. This work proposes a new autonomous path‐planning algorithm for exploration in an unknown environment based on paired frontiers, which we call internal and external frontiers algorithm (IEFA), that defines extended area for navigation of the mobile robot. For each exploration round, the robot defines external frontiers using the maximum range of sensors. Then, the robot generates internal frontiers, that is, pairs of external frontiers by varying the range of sensors. According to the size of each pair of frontiers, the algorithm generates the target point for robot navigation. The frontiers of internal layer are utilized as a main parameter for generation of next exploration point. We evaluated the proposed algorithm in simulation environments using the ROS toolbox of MATLAB and compared it with two previous exploration algorithms. From the experimental results, the proposed algorithm showed from 31% to 85% better performance in the path distance than previous algorithms.
•Carbon nanotube sponge is a promising adsorbent for vapor preconcentrator.•Intrinsic resistivity facilitates a direct desorption without heating elements.•Rapid thermal heating at a rate of 481.5 ...℃/s allows a narrow bandwidth of 0.74 s.•Enrichment factor of 300 is achieved for benzene at a sampling volume of 100 mL.
A carbon nanotube (CNT) sponge was synthesized and examined as an adsorptive material for a thermally desorbed preconcentrator for volatile organic compounds (VOCs). The porous sponge-like material, retaining the intrinsic properties of individual multiwalled (MW) CNTs, was fabricated using spray pyrolysis chemical vapor deposition (CVD). The square pillar form of the CNT sponge was enclosed in a 1/4″ glass tube with fittings for flow-through sampling. Flow of a direct current through the CNT sponge allowed rapid thermal heating to a surface temperature of 264.7 ℃ at a rate of 481.5 ℃/s and a narrow desorption bandwidth of 0.74 s. The preconcentration concept was validated using gas chromatographic analysis of an aromatic VOC mixture, including benzene, toluene, ethylbenzene, and o-xylene (BTEX) vapors at concentrations of 100 parts per billion (ppb). With an adsorption volume of only 100 mL, the enrichment factor of each analyte was 300 (B), 240 (T), 210 (E), and 200 (X), enabling sensitive measurements with limits of detection at the parts per trillion level. Sequential desorption experiments confirmed that a single desorption process evaporates all the analytes inside the preconcentrator with >96% efficiency. There was no humidity effect and no sign of performance degradation after continuous operation for 45 repeated cycles. These results demonstrate that CNT sponges are a suitable material for the enrichment and sensitive determination of VOCs at trace levels. Thus, CNT sponge preconcentrators are advantageous in a variety of applications that permit fast and accurate real-time measurements, including ambient air and workplace air monitoring.
We investigated the effect of the thickness of superconducting layer on the competition between ferromagnetism and superconductivity. The epitaxial bilayer systems consisting of GdBa2Cu3O7-x (GdBCO) ...with varying thickness and La0.7Sr0.3MnO3 (LSMO) were grown on (001) SrTiO3 (STO) substrate. From the spectroscopic measurements, we observed an existence of a possible structural coupling between the GdBCO and the LSMO layers. The structural coupling is found to depend on the GdBCO thickness and to induce different types of strain on both layers, leading to the competition between the ferromagnetic and the superconducting orders. With respect to the flux pinning, an additional pinning contribution besides magnetic pinning induced by LSMO is emerged by the structural coupling, which is attributed to local atomic disorder. Controlling the thickness of GdBCO modifies the structural coupling and consequently, the degree of additional pinning contribution aroused by disorder on the CuO2 plane can be adjusted. An appropriate structure with a certain thickness amplifies the hybrid effect of magnetic pinning and additional pinning, resulting in an enhancement of the critical current density at high magnetic fields. Our findings suggest a possibility of controlling complex flux pinning through an optimization of structural coupling between the GdBCO and the LSMO layers.
Dear Editor,
Eliminating misfolded or mistargeted proteins is crucial for cell viability because these proteins accumulate as non-specific aggregates, which can be toxic to the cell （Lee et al., ...2009; Sroka et al., 2009）. Previously, we have shown that in ppi2 （plastid protein import 2） mutant plants, the transcript levels of Hsc70-4 （one isoform of the Hsc70 family） and CHIP （an E3 ligase） were highly upregulated, which ultimately plays crucial roles in proteasomal degradation of unimported plastid proteins （Lee et al., 2009）. We also found that, along with those of Hsc70-4 and CHIP, the transcript level of AtBAG1 （Arabidopsis thaliana Bcl2-associated athanogene 1） in the ppi2 mutant was 2.38-fold higher than that in the wild-type （Lee et al., 2009）.
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