Locomotion Control of a Compliant Legged Robot from Slow Walking to Fast Running Regular Paper

In this paper, we propose a locomotion control method for a compliant legged robot from slow walking to fast running. We also examine the energy efficiency of the compliant legged robot controlled by the proposed locomotion control method. Experimentally, we obtain the robot running speed of about 4.3m/s with the initial compliant leg length of 0.1m. In addition, we obtain very good energy efficiency. In the best case, the mechanical cost of transport(Cmt), known as an energy efficiency measure, is obtained at about 0.2. Comparing with the other energy efficient robots, our robot exhibits very good energy efficiency. © 2012 Kim et al.; licensee InTech.1

A Compact Vertical Scanner for Atomic Force Microscopes

A compact vertical scanner for an atomic force microscope (AFM) is developed. The vertical scanner is designed to have no interference with the optical microscope for viewing the cantilever. The theoretical stiffness and resonance of the scanner are derived and verified via finite element analysis. An optimal design process that maximizes the resonance frequency is performed. To evaluate the scanner’s performance, experiments are performed to evaluate the travel range, resonance frequency, and feedback noise level. In addition, an AFM image using the proposed vertical scanner is generated

A Highly Sensitive Enzyme-Amplified Immunosensor Based on a Nanoporous Niobium Oxide (Nb2O5) Electrode

We report on the development of an enzyme-amplified sandwich-type immunosensor based on a thin gold film sputtered on an anodic nanoporous niobium oxide (Au@Nb2O5) electrode. The electrocatalytic activity of enzymatically amplified electroactive species and a stable electrode consisting of Au@Nb2O5 were used to obtain a powerful signal amplification of the electrochemical immunobiosensor. The method using this electrochemical biosensor based on an Au@Nb2O5 electrode provides a much better performance than those based on conventional bulk gold or niobium oxide electrodes. Our novel approach does not require any time-consuming cleaning steps to yield reproducible electrochemical signals. In addition, the strong adhesion of gold films on the niobium oxide electrodes offers a very stable substrate during electrochemical biosensing. Cyclic voltammetry measurements indicate that non-specific binding of proteins to the modified Au@Nb2O5 surface is sufficiently low to be ignored in the case of our novel system. Finally, we demonstrated the ability of the biosensor based on an Au@Nb2O5 offering the enhanced performance with a high resolution and sensitivity. Therefore, it is expected that the biosensor based on an Au@Nb2O5 has great potential for highly efficient biological devices

Kerberos based authentication for inter-domain roaming in wireless heterogeneous network

AbstractAn increased demand in ubiquitous high speed wireless access has led integration of different wireless technologies provided by different administrative domains creating truly a heterogeneous network. Security is one of the major hurdles in such network environment. As a mobile station moves in and out of the coverage area of one wireless network to another, it needs to be authenticated. The existing protocols for authentication of a mobile station are typically centralized, where the home network participates in each authentication process. It requires home network to maintain roaming agreement with all other visiting networks. Moreover, the round trip time to home network results high latency. This paper is focused on developing authentication protocol for wireless network irrespective of the technologies or the administrative domain. We propose a secure protocol which adopts strong features of Kerberos based on tickets for rigorous mutual authentication and session key establishment along with issuance of token so that the mobile station can have access to not only the roaming partner of home network but also to the roaming partner of previous visited networks. The performance evaluation and comparative analysis of the proposed protocol is carried out with the already implemented standard protocols and most remarkable research works till date to confirm the solidity of the results presented

Noxious gas detection using carbon nanotubes with Pd nanoparticles

Noxious gas sensors were fabricated using carbon nanotubes [CNTs] with palladium nanoparticles [Pd NPs]. An increase in the resistance was observed under ammonia for both CNTs and CNT-Pd sensors. Under carbon monoxide [CO], the two sensors exhibited different behaviors: for CNT sensors, their resistance decreased slightly with CO exposure, whereas CNT-Pd sensors showed an increase in resistance. The sensing properties and effect of Pd NPs were demonstrated, and CNT-Pd sensors with good repeatability and fast responses over a range of concentrations may be used as a simple and effective noxious gas sensor at room temperature

Antibacterial and synergistic effects of Nardostachytis rhizoma extracts on methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is a serious clinical problem worldwide. Few new drugs are available against MRSA, because it has the ability to acquire resistance to most antibiotics which consequently increases the cost of medication. In the present study, the antibacterial activity of Nardostachytis rhizoma was investigated. The most effective method is to develop antibiotics from the natural products without having any toxic or side effects. Therefore, there is a need to develop alternative antimicrobial drugs for the treatment of infectious diseases. The use of two drugs in combination is a good alternative to slow the process of developing drug resistance and to restore the effectiveness of drugs that are no longer prescribed. Combination therapy is the most commonly recommended empirical treatment for bacterial infections in intensive care units, where monotherapy may not be effective against all potential pathogens, and for preventing the emergence of resistant. Five clinical isolates (MRSA) were obtained from five different patients at Wonkwang University Hospital (Iksan, South Korea). The other two strains were S. aureus ATCC 33591 (methicillin-resistant strain) and S. aureus ATCC 25923 (methicillin-susceptible strain). Antibacterial activity (minimal inhibitory concentrations, MICs) was determined by broth dilution method, disc diffusion method, MTT test and checkerboard dilution test. Antimicrobial activity of n-hexane fraction of N. rhizoma was significant. Against the seven strains, the disc diffusion test was in the range of 14 to 18 mm and had a MICs ranging from 31.25 to 125 ìg/ml. FICI values for n-hexane fraction (HFL) of N. rhizome + ampicillin (AM) and HFL + oxacillin (OX) were 0.1875 and 0.078125-0.09375, showing the increase of synergistic effect. When combined together, these antibiotic effects were dramatically increased. These effective combinations could be new promising agents in the management of MRSA and MSSA.Key words: Nardostachytis rhizoma, synergism, antibacterial, methicillin-resistant Staphylococcus aureus (MRSA)

The Effect of Biomechanics Information on Driver Swing Learning of Intermediate Golfers

PURPOSE This study investigates the effectiveness of biomechanics information on intermediate golfers driver swing learning. It analyzes changes in center of pressure (COP) patterns, GRF Direction Inclination, driver performance, and learners psychological responses to determine the learning effects. METHODS Subjects were 32 right-handed male golfers (handicap 15-23) who had no difficulty in performing the golf driver swing (Full swing). Four groups were selected, BF (Biomechanics Feedback group), BVC (Biomechanics Verbal Cue group), CB (Combination group), and CT (Control group), and assigned randomly. Driver swing learning showed results after 6 weeks,and a transfer test was conducted 1 week after the completion of the learning. RESULTS Analysis of COP patterns and GRF Direction Inclination indicated changes in the BF, BVC, and CB groups. Furthermore, analysis of driver distance (m), club head speed (km/h), and ball spin rate (rpm) revealed that during the 6-week acquisition phase, all three groups (excluding the control group) showed improvements in driver distance, club head speed, and ball spin rate. However, there were no statistically significant differences among the groups. In contrast, the transfer test showed statistically significant differences among the groups, with the CB group exhibiting the highest driver distance. Learners' psychological responses during the learning process were trust, understanding, and satisfaction. The understanding factor was relatively higher in the CB and BVC groups compared to the BF group. CONCLUSIONS In summary, biomechanics information (BI) was effective in improving driver performance, and changesappeared in the COP pattern and GRF Direction Inclination, indicating a change in movement. Therefore, BI can be fully utilized for athletes or high-level advanced players and for motor learning for intermediate-level students.However, BI can only improve learning effects by strengthening learners' “understanding” when visual feedback forms and verbal cues are provided together

In-situ fabrication of cobalt-doped SrFe2As2 thin films by using pulsed laser deposition with excimer laser

The remarkably high superconducting transition temperature and upper critical field of iron(Fe)-based layered superconductors, despite ferromagnetic material base, open the prospect for superconducting electronics. However, success in superconducting electronics has been limited because of difficulties in fabricating high-quality thin films. We report the growth of high-quality c-axis-oriented cobalt(Co)-doped SrFe2As2 thin films with bulk superconductivity by using an in-situ pulsed laser deposition technique with a 248-nm-wavelength KrF excimer laser and an arsenic(As)-rich phase target. The temperature and field dependences of the magnetization showing strong diamagnetism and transport critical current density with superior Jc-H performance are reported. These results provide necessary information for practical applications of Fe-based superconductors.Comment: 8 pages, 3figures. to be published at Appl. Phys. Let