Observation and characterization of mode splitting in microsphere resonators in aquatic environment

Whispering gallery mode (WGM) optical resonators utilizing resonance shift (RS) and mode splitting (MS) techniques have emerged as highly sensitive platforms for label-free detection of nano-scale objects. RS method has been demonstrated in various resonators in air and liquid. MS in microsphere resonators has not been achieved in aqueous environment up to date, despite its demonstration in microtoroid resonators. Here, we demonstrate scatterer-induced MS of WGMs in microsphere resonators in water. We determine the size range of particles that induces MS in a microsphere in water as a function of resonator mode volume and quality factor. The results are confirmed by the experimental observations.Comment: 4 Pages, 5 Figures, 13 Reference

Studies on Covariance Selection Models : Stepwise Procedure and Local Influence

Analysis of covariance selection models is a useful multivariate method to analyze the covariance structure of a multivariate normal distribution. It is used to reveal cause-and-effect relationships. In the present paper we review the theory and study numerically how the stepwise procedure of covariance selection works in actual data analysis. Then we try to develop a method of influence analysis in covariance selection, and show a numerical example to illustrate the usefulness of the method of influence analysis

Interface analysis between GSVML and HL7 version 3

AbstractIn order to realize gene-based medicine, a number of key challenges must be overcome. Construction of infrastructure capable of integrating genetic and clinical information is one of those challenges. The Genomic Sequence Variation Markup Language (GSVML) and the Health Level Seven Version 3 (HL7v3) are important electronic data exchange standards for clinical genome infrastructure, and compatibility between these two standards will promote the above integration. In this study, we analyzed the interface between GSVML and HL7v3, primarily for the Clinical Genomics Domain, from a view of the GSVML, and were able to create a blueprint for a functional interface between GSVML and HL7v3. We expect that these analytical results will help accelerate the realization of gene-based medicine

Demonstration of mode splitting in an optical microcavity in aqueous environment

Scatterer induced modal coupling and the consequent mode splitting in a whispering gallery mode resonator is demonstrated in aqueous environment. The rate of change in splitting as particles enter the resonator mode volume strongly depends on the concentration of particle solution: The higher is the concentration, the higher is the rate of change. Polystyrene nanoparticles of radius 50nm with concentration as low as 5x10^(-6)wt% have been detected using the mode splitting spectra. Observation of mode splitting in water paves the way for constructing advanced resonator based sensors for measuring nanoparticles and biomolecules in various environments.Comment: 8 pages, 4 figures, 21 Reference

Detecting single viruses and nanoparticles using whispering gallery microlasers

Detection and characterization of individual nano-scale particles, virions, and pathogens are of paramount importance to human health, homeland security, diagnostic and environmental monitoring[1]. There is a strong demand for high-resolution, portable, and cost-effective systems to make label-free detection and measurement of individual nanoparticles, molecules, and viruses [2-6]. Here, we report an easily accessible, real-time and label-free detection method with single nanoparticle resolution that surpasses detection limit of existing micro- and nano-photonic devices. This is achieved by using an ultra-narrow linewidth whispering gallery microlaser, whose lasing line undergoes frequency splitting upon the binding of individual nano-objects. We demonstrate detection of polystyrene and gold nanoparticles as small as 15 nm and 10 nm in radius, respectively, and Influenza A virions by monitoring changes in self-heterodyning beat note of the split lasing modes. Experiments are performed in both air and aqueous environment. The built-in self-heterodyne interferometric method achieved in a microlaser provides a self-reference scheme with extraordinary sensitivity [7,8], and paves the way for detection and spectroscopy of nano-scale objects using micro- and nano-lasers.Comment: Main Text: 14 pages, 5 figures, 27 references. Supplement: 26 pages, 12 figures, 26 reference

Goal-directed Imitation with Self-adjusting Adaptor Based on a Neural Oscillator Network

An innovative framework of imitation between dissimilar bodies is proposed to automatically achieve the goal of the perceived behavior. Biologically inspired control based on central pattern generators currently gains increasing attention to embody human-like rhythmic motions to humanoid robots. However, this control approach suffers from highly nonlinear dynamics of neural systems, difficulty of motion pattern generation, uncertainty of behavior between neural systems and biomechanics, and so on. To cope with these problems, the imitation technique is employed in this work. We first propose the self-adjusting adaptor to easily generate an appropriate motion pattern by modifying the perceived motion toward attaining the goal of the behavior. Secondly, we verify the property of entrapment of neural oscillator network in the proposed adaptor to duplicate the regenerated motion pattern. In the numerical simulations of biped locomotion, the perceived pattern data is regenerated to keep the direction of the foot contact force identical between the demonstrator and the imitator Also, the neural oscillator is entrained by external signals under stable conditions. To the best of the authors' knowledge, this paper is the first work to validate the advantages of neural oscillator networks as a tool of imitatio

Imitation Learning of Humanoid Locomotion Using the Direction of the Landing Foot

Since it is quite difficult to create motions for humanoid robots having fairly large numbers of degrees of freedom, it would be very convenient indeed if robots could observe and imitate what they want to create. Toward this end, this paper discusses how humanoid robots learn through imitation considering that demonstrator and imitator robots may have different kinematics and dynamics. As part of a wider interest in humanoid motion generation in general, this work mainly investigates how imitator robots adapt a reference locomotion gait captured from a demonstrator robot. Specifically, the self-adjusting adaptor is proposed, where the perceived locomotion pattern is modified to keep the direction of lower leg contacting the ground identical between the demonstrator and the imitator, and to sustain the dynamic stability by controlling the position of the center of mass. The validity of the proposed scheme is verified through simulations on OpenHRP and real experiments

Development of Wrist Interface Based on Fully Actuated Coaxial Spherical Parallel Mechanism for Force Interaction

To develop a wrist robotic exoskeleton-type interface (REI) for force interaction, it should have a suitable range of motion similar to human wrist activities of daily living, large torque output performance, and low moving parts inertia for dynamic motion response to cover the human behavior frequency. In this paper, a wrist REI based on a fully actuated coaxial spherical parallel mechanism (CSPM) is proposed to satisfy the aforementioned features. The fully actuated CSPM-based wrist REI (FC-WREI) has the characteristics of pure rotation similar to the human wrist, high torque output by parallel torque synthesis, and low moving parts inertia due to the base arrangement of the actuators. Due to the mechanical advantages and design optimization, the FC-WREI maximally provides torque as much as 56.49–130.43% of the maximum isometric torque of the human wrist, while providing a consistent range of motion to the human wrist without interference problem. Moreover, it is confirmed that the inertia of the FC-WREI is up to 5.35 times lower than similar devices. These advantages of the FC-WREI mean that the device is applicable to various fields of REIs for force interaction