Using neural networks for learning motion controllers from motion capture data is becoming popular due to the natural and smooth motions they can produce, the wide range of movements they can learn ...and their compactness once they are trained. Despite these advantages, these systems require large amounts of motion capture data for each new character or style of motion to be generated, and systems have to undergo lengthy retraining, and often reengineering, to get acceptable results. This can make the use of these systems impractical for animators and designers and solving this issue is an open and rather unexplored problem in computer graphics. In this paper we propose a transfer learning approach for adapting a learned neural network to characters that move in different styles from those on which the original neural network is trained. Given a pretrained character controller in the form of a Phase‐Functioned Neural Network for locomotion, our system can quickly adapt the locomotion to novel styles using only a short motion clip as an example. We introduce a canonical polyadic tensor decomposition to reduce the amount of parameters required for learning from each new style, which both reduces the memory burden at runtime and facilitates learning from smaller quantities of data. We show that our system is suitable for learning stylized motions with few clips of motion data and synthesizing smooth motions in real‐time.
In this paper, we propose a novel approach for the classification and retrieval of interactions between human characters and objects. We propose to use the interaction bisector surface (IBS) between ...the body and the object as a feature of the interaction. We define a multi‐resolution representation of the body structure, and compute a correspondence matrix hierarchy that describes which parts of the character's skeleton take part in the composition of the IBS and how much they contribute to the interaction. Key‐frames of the interactions are extracted based on the evolution of the IBS and used to align the query interaction with the interaction in the database. Through the experimental results, we show that our approach outperforms existing techniques in motion classification and retrieval, which implies that the contextual information plays a significant role for scene and interaction description. Our method also shows better performance than other techniques that use features based on the spatial relations between the body parts, or the body parts and the object. Our method can be applied for character motion synthesis and robot motion planning.
In this paper, a new dance training system based on the motion capture and virtual reality (VR) technologies is proposed. Our system is inspired by the traditional way to learn new ...movements-imitating the teacher's movements and listening to the teacher's feedback. A prototype of our proposed system is implemented, in which a student can imitate the motion demonstrated by a virtual teacher projected on the wall screen. Meanwhile, the student's motions will be captured and analyzed by the system based on which feedback is given back to them. The result of user studies showed that our system can successfully guide students to improve their skills. The subjects agreed that the system is interesting and can motivate them to learn.
Human motion indexing and retrieval are important for animators due to the need to search for motions in the database which can be blended and concatenated. Most of the previous researches of human ...motion indexing and retrieval compute the Euclidean distance of joint angles or joint positions. Such approaches are difficult to apply for cases in which multiple characters are closely interacting with each other, as the relationships of the characters are not encoded in the representation. In this research, we propose a topology-based approach to index the motions of two human characters in close contact. We compute and encode how the two bodies are tangled based on the concept of rational tangles. The encoded relationships, which we define as TangleList, are used to determine the similarity of the pairs of postures. Using our method, we can index and retrieve motions such as one person piggy-backing another, one person assisting another in walking, and two persons dancing/wrestling. Our method is useful to manage a motion database of multiple characters. We can also produce motion graph structures of two characters closely interacting with each other by interpolating and concatenating topologically similar postures and motion clips, which are applicable to 3D computer games and computer animation.
In this paper, we propose a new method to simulate human gait motion when muscles are weakened. The method is based on the enhanced version of three-dimensional linear inverted pendulum model that is ...used for generation of gait in robotics. After the normal gait motion is generated by setting the initial posture and the parameters that decide the trajectories of the center of mass and angular momentum, the muscle to be weakened is specified. By minimizing an objective function based on the force exerted by the specified muscle during the motion, the set of parameters that represent the pathological gait was calculated. Since the number of parameters to describe the motion is small in our method, the optimization process converges much more quickly than in previous methods. The effects of weakening the gluteus medialis, the gluteus maximus, and vastus were analyzed. Important similarities were noted when comparing the predicted pendulum motion with data obtained from an actual patient.
This paper examines the influences of ionizable thiol monolayers on the interfacial charge-transfer rates for redox-active ions by electrochemical impedance spectroscopy. Whereas short-chain thiols ...such as 4-aminothiophenol hardly affected the charge-transfer resistance for Ru(NH
3)
6
3+ having a high standard heterogeneous rate constant, the 11-mercaptoundecanoic acid monolayer raised this resistance to 3×10
4 times that observed at a bare electrode in acidic solutions. As the terminal carboxyl group ionized, the charge-transfer resistance decreased by a factor of 300 because of a double-layer effect. When 3-mercaptopropionic acid was mixed with 1-hexadecanethiol, the charge-transfer resistance varied over four orders of magnitude with the composition of the two-component monolayer. The apparent rate constant for indigotetrasulfonate at 4-aminothiophenol-modified electrodes decreased by a factor of 25–30 as the solution pH varied from 4 to 2. This decrease was opposite to the change expected from protonation of the terminal amino group. It can be ascribed to a strong binding interaction between the redox anion and the positively charged monolayer.
A permeation measuring system with a nickel membrane of 30μm thickness was installed in a spherical tokamak QUEST. The membrane was located near the mid plane of the tokamak so that one side of the ...membrane was faced to the plasma. After the membrane was heated to 502K, hydrogen plasma was discharged using 2.45GHz RF system. The permeation flux through the membrane increased with a proper time-lag, that is, a significant plasma-driven permeation was observed. A numerical calculation of the diffusion equation under recombination boundary conditions was successfully conducted to simulate the transient permeation behavior. The recombination coefficients, estimated in a temperature range of 412–575K, can be explained by a model of thermally activated processes. Stable operation of the permeation system indicates the suitability of this system for the measurements of atomic flux with known diffusivity and recombination coefficients.
This paper describes electrochemical characteristics of poly(methylene blue) electrolytically deposited on glassy carbon and examines the electrocatalytic activity of the polymer toward oxidation of ...the coenzyme NADH. Redox‐active properties of the cationic polyelectrolyte arose from both electron self‐exchange between electroactive sites and a high ionic film‐conductivity. The diffusion coefficient of charge carriers in the film increased with decreasing solution pH, indicating the pH dependence of the electron diffusion coefficient. The electrocatalytic oxidation of NADH at the polymer‐modified electrode proceeded via an intermediate charge‐transfer complex of the reduced polymer with the oxidized coenzyme. The complex dissociated more rapidly into the oxidation products as the reduced polymer protonated. Thus, the rate constant for the cross‐exchange reaction rose with a decrease in pH. For NADH oxidation, the polyelectrolyte exhibited an electrocatalytic activity higher than the monomeric dye because of a stronger oxidizing power of the second oxidized form of the polymer.
This report describes electrochemical and optical properties of azine-loaded Nafion® film electrodes that generate redox-activated optical signal. The apparent charge diffusion coefficient in the ...film decreased abruptly as the solution pH increased from 0.4 to 3, probably because deprotonation of the dyes lowered the rate of intermolecular electron hopping. Reversible switching of the fluorescence of phenosafranine was performed by electrochemical oxidation/reduction cycles. Both of the redox couple were isolable and stable; the reduced form was non-fluorescent, whereas the oxidized form was strongly fluorescent. Since the photonic output depended on chemical binding, the electrode system could operate as a dual-mode switching device. The second protonation of the dye molecule changed the fluorescence intensity sufficiently for chemical signaling of the photonic output, because the fully protonated oxidized-form was non-fluorescent; however, a p
K
a1 of 0.8 was too low to change the pH rapidly. 1,1′-ferrocenedimethanol quenched the fluorescence of the oxidized form efficiently to cause the ‘switching off’ of fluorescence. In the presence of the guest, however, the dye-loaded film did not recover the fluorescent state at any potential, because the cationic dye formed a nonfluorescent complex with the guest incorporated into the film.
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