Abstract In the field of 4‐D space visualization, the information of 4‐D space is obtained by projecting 4‐D data onto 3‐D space. Most of the previous research has been aimed at the recognition of 4‐D space, whereas the target of the recognition has been limited to the geometrical information of 4‐D objects in 4‐D space or static spatial information without dynamics. Our research aims to develop a visualization system for providing the human experience of the physics‐based environment in 4‐D space. In this research, we mainly focus on collision detection and the behaviour of 4‐D objects in 4‐D space in order to construct the physics‐based environment of 4‐D space. Our contribution in this paper is the development of a collision detection algorithm for 4‐D objects and a calculation method for physics based behaviour of 4‐D objects. Our proposed collision detection algorithm is based on the intersection test of tetrahedrons in 4‐D space, so that 4‐D objects in our system is represented as tetrahedral meshes. The tetrahedron‐based collision detection algorithm is performed by a combination of half‐space tests with the use of 5‐D homogeneous processing to enhance the calculation accuracy of the collision detection. Our proposed method calculates the behaviour of the 4‐D objects after the collision by solving the motion equation based on the principle of physics. Consequently, the visualization system with the proposed algorithm allows us to observe the physics‐based environment in 4‐D space.

This paper introduces a novel interactive system for presenting 4D objects in 4D space through tactile sensation. A user is able to experience 4D space by actively touching 4D objects with the hands, where the hand holding the controller is physically stimulated at a three-dimensional hypersurface of the 4D object. When a hand is placed on the 3D projection of a 4D object, the force generated at the interface between the hand and the object is calculated by referring to the distance from the viewpoint to each point in the frontal surface of the object. The calculated force in the hand is converted to the vibration patterns to be displayed from the tactile glove. The system supplements the 4D information such as tilt or unevenness, which is difficult to be visually recognized.

In this study, a wearable Braille display is developed to present Braille information on two fingers (an index finger and a middle finger). We use shape-memory alloy (SMA) wires as an actuator that generates micro-vibration by applying pulse current. Possible vibrating patterns are firstly examined to find the best frequency and timing for presenting Braille information on two fingers. The display has six dots to present one Braille character at one time. For Braille presentation, the actuators in the display are driven by pulse current with the same or different frequencies and different time durations. In addition, to increase recognition rate, we add a button by which a subject starts or restarts Braille presentation. Users' experiments are conducted to verify the ability of the Braille display.

The objective of this study is to understand the learned-strategy of neural network-controlled robots in relation to their physical learning environments by visualizing the internal layer of the neural network. During the past few years, neural network-controlled robots that are able to learn in physical environments are becoming more common. While they can autonomously acquire strategy without human supervisions, it is becoming difficult to understand their strategy, especially when the robots, their environments and their tasks are complicated. In the critical fields that involve human safety, as in self-driving vehicles or medical robots, it is important for human to understand the strategies of the robots. In this preliminary study, we propose a hierarchical neural network with a two-dimensional topographical internal representation for training robots in physical environments. The 2D representation can then be visualized and analyzed to allow us to intuitively understand the input-output strategy of the robots in the context of their learning environments. In this paper, we explain about the learning dynamics of the neural network and the visual analysis of some physical experiments.

Shape-memory alloys (SMAs) are metal which have the shape memory effects. By forming them to thin wires, they can shrink at a certain temperature; and then extend to original length after cooling below this temperature, thus shape-memory effect is observed. When pulse current is applied to a SMA wire, Joule heat generated inside makes the wire shrink about 5% of its length, and returns to the origin length when the pulse stops, which generate vibration in accordance with the frequency of the current. A novel designed actuator using the vibration of two SMA wires is proposed in this paper. The actuator has compact size and low energy consumption of milliwatts order. Tactile sensation is one of the important ways in human's five senses, which are used to acquire information from surrounding environment. In this paper, we are trying to transmit recognized information by translating it to tactile sensation perceived by skin around eyes. We divide the skin area around eyes into 4 zones, and design two tactile display prototypes. By installing multiple actuators in prototypes and applying pulse signals with different parameters, we conduct experiments to find optimal driving parameters to generate tactile sensation in designated skin areas. The higher-level perception in these area is tested by combining different parameters and stimulation patterns. Finally, information transmission is evaluated by the feedback from subjects and it turns out the proposed system performs well. In the final part we also propose potential applications of this system.

In this paper, we propose a novel method for a humanoid robot to recover its standing posture from different fallen postures. In the proposed method, the robot estimates its posture using the ground-contacting information, which is sensed by the joint angle information and pressure sensors attached to the whole body. Then, the robot searches a motion sequence based on the estimated posture to stand up. The robot preserves every successful motion sequence into the tree structure to be reused in the next time. To verify the proposed algorithm, we conducted evaluation experiments by employing a real robot. The results show that the proposed method enables the robot to successfully search the motion sequence for standing up from the fallen posture.

In human speech, the timing function is important for determining its duration, stress and rhythm; however, little attention has been paid to these issues when building a speech synthesis system. In the human brain, the cerebellum plays a key role in the coordination, precision and timing of motor responses. We have developed a talking robot, which generates human-like vocal sounds using a simplified cerebellum-like neural network model as the timing function. The model was designed using the System Generator software in Matlab environment and the timing duration of trained speech was estimated using hardware co-simulated with a field programmable gate array board (FPGA). The timing information obtained from the co-simulation, together with the output motor vector, is sent to the talking robot controller in order to generate vowels of short, medium and long duration. Using this model for short-range timing of less than 1200 milliseconds, we verify that the short-range learning capability of the cerebellar-like neural network is applicable to the speaking robot for generating a human-like speech with prosodic features.

The authors are developing a talking robot which is a mechanical vocalization system modeling the human articulatory system. The talking robot is constructed with mechanical parts that are made by referring to human vocal organs biologically and functionally. In this study, a newly redesign artificial vocal cord is developed for the purpose of extending the speaking capability of the talking robot. The artificial vocal cord is developed using functional approach. A thin layer of rubber band with a width of 7mm is attached on a plastic body in a sealed chamber creates an artificial sound source. The fundamental frequency of the sound source vary from 80Hz to 280 Hz depending on the pressure to the rubber band and the curving shape of the rubber band. The curving shape of the rubber band is adjustable by an innovative design mechanism driven by a servo motor. The amount of air pressure applied to the rubber band is controlled by another servo motor which is referred as volume motor in this study. The experiment to verify the speak capability of the talking robot with this newly redesigned vocal cord is conducted by letting the robot generating five vowel sounds with difference combination of 20 levels of rubber band shape and 10 levels of air pressure input. The pitch and volume of each sound is extracted to determine the effect of the rubber band shape and the pressure input on the output sound. The result shows that this newly redesigned vocal cord greatly increase the speaking capability of the talking robot, especially its singing performance.

An estimated number of 420 million people in the world had diabetes mellitus in 2014, which had become quadruple since 1980, and the number is estimated to be 700 million by 2025. Diabetes mellitus is a group of metabolic diseases, which causes high blood sugar to a person, due to the functional problems of the pancreas or the metabolism. Patients of untreated diabetes would be damaged by the high blood sugar in vessels, and this starts to destroy capillary vessels to lower the sensitivity of tactile sensations, then effects to various organs and nerve systems. Diabetic peripheral neuropathy is one of the complications of diabetes mellitus, and the authors pay attention to the decline of the sensitivity of tactile sensations in the early stage of diabetes. By using a novel micro-vibration actuator that employs a shape-memory alloy wire, we develop a non-invasive screening device of the level of diabetes based on the perception of micro-vibration patterns. Experiments are conducted in a medical clinic, and the relation between the tactile stimuli and the medical diagnosis of diabetes are examined.

In the recognition of an object situated in front of us, we firstly watch it and then try to touch it to feel the tactile and haptic sensation to be perceived by our hands. Various virtual reality and augmented reality systems have been introduced with the growing computational powers, however visual and auditory information related with a virtual object is mainly presented simultaneously to a user for enhancing the reality. If we consider the real situation of a user to try to recognize an object in the living environment, tactile and haptic information is assumed to be rather important for the better interaction with the object. In this study, we develop a hapto-tactile display that covers the movable range of a human arm in the tactual search for presenting tactile sensation of a virtual object. We design and construct a tactile pad to be fixed at the tip of a passively-driven haptic arm, and the tactile sensation and haptic force are simultaneously displayed to a user wearing the pad in the hand. The development of the hapto-tactile display for human tactile search will be described in this paper, together with an experiment to verify the validity of the system.

With the widespread availability of computers and mobile devices, we use them for daily communication by exchanging visual and verbal/non-verbal media. We obtain various information from multimedia devices, and such devices recently have a touch panel interface to allow a user to intuitively and interactively use them. A touch panel consists of a touch-sensitive panel and a graphical display, and accepts user's intuitive touch inputs together with visual and auditory feedback. With the employment of touch actions in such interface devices, tactile feedback will be expected, if we consider the manipulation of a real object. For presenting tactile feedback, some tactile actuators have been introduced recently, however these actuators require the reference from real objects to generate the appropriate tactile sensations, and the input data to be associated with the output tactile sensations should be precisely prepared in the design of such systems. This study introduces a tactile pen to work with a touch screen, together with an algorithm to automatically generate parameters from an object's picture for driving tactile actuators. A tactile presentation system with a visual display is constructed, and the validity of the texture sensations is verified by a user's experiment.

An innovative tactile pad that presents various tactile sensations synchronizing with moving pictures is presented in this paper. To display tactile/touch sensations from a pad, a tactile display panel is designed by employing 10 micro-vibration actuators that provide tactile-stimulation sources using shape memory alloy wires. With the employment of the human higher-level perception caused by appropriate micro-vibratory stimuli, the resolution of the designed tactile display panel increases more than three times, so that people perceive various tactile sensations with high resolution enough for the better reality. By employing a webcam to capture moving pictures, the tactile pad system automatically recognizes the texture information contained in the scene, which are associated with tactile information to be output from the tactile pad. In order to let people reasonably perceive the presented tactile sensations, the developed system automatically translates visual information to tactile sensation. For verifying the effectiveness of the developed vision-based tactile pad system, experiments are conducted and the results are presented.

Diabetes mellitus is a group of metabolic diseases which causes high blood sugar to a person, due to the functional problems of the pancreas or the metabolism. For a person with diabetes, glucose would not be used properly in the metabolic system, and cause health problems, such as polyphagia, polyuria and polydipsia, since glucose is the main source of energy for the body cells. Symptoms of untreated diabetes would be damaged by the high blood sugar in vessels, and this starts to destroy capillary vessels to lower the sensitivity of tactile sensations, then effects to various organs and nerve systems. The authors pay attention to the decline of the sensitivity of tactile sensations associated with diabetes, and develop a non-destructive screening method of the level of diabetes using a novel micro-vibration actuator that employs a shape-memory alloy wire. The actuators are arranged in an array, and various tactile stimuli are generated by just controlling the driving current signals. The tactile stimuli are presented to symptom's, index and middle fingers., and he/she responds to the stimuli by answering how they are perceived. We made an experiment in a medical clinic., and examined the relation between the Hb Al C values and tactile stimuli.

Humans communicate with each other by using not only verbal media but also the five senses such as vision, audition, olfaction and tactile sensations. Various devices and systems have been introduced for supporting human communication, and most of them are based on visual and auditory media. For presenting tactile sensations, some tactile actuators have been introduced recently, however these actuators require real objects to generate the various tactile sensations and input data to be associated with output tactile sensations should be prepared manually by a user. This study introduces an algorithm to automatically generate parameters from an object's image for driving tactile actuators. A tactile presentation system is constructed, and the validity of the texture sensations is verified by a user's experiment.

A novel portable Braille display for mobile use is constructed by employing the micro-vibrations generated by small Shape Memory Alloy (SMA) wires. According to the characteristics of the shrinkage and expansion of a SMA wire formed into a diameter with 50 micro-meters, a vibration actuator which can be driven by several to 300 hertz pulse signals has been developed. To present Braille information for the blind, the vibration actuator is used instead of conventional Braille dots. A new method for presenting Braille information is proposed to apply the developed actuator into Braille display. The effectiveness of the proposed Braille display is verified by experimental results.

A novel micro-vibration actuator using a shape-memory alloy (SMA) wire is being developed for the presentation of tactile sensations to a human skin. In this study, the SMA wire is arranged two dimensionally to construct a compact Braille display for the blind. The display is driven by electric current pulse for mobile use to present Braille information. The display was evaluated in a school for the blind, and the results are presented in the paper.

A talking and singing robot which adaptively learns the vocalization skill by an auditory feedback learning is being developed. In vocalization, the vibration of vocal cords generates a source sound, and then the sound wave is led to a vocal tract, which works as a resonance filter to determine the spectrum envelope. The robot consists of motor-controlled vocal organs such as vocal cords, a vocal tract and a nasal cavity to generate a natural voice imitating a human vocalization. The paper briefly introduces the construction of vocal cords and vocal tract for the realization of the talking robot, and then describes how the robot autonomously acquires the vocalization skill in the auditory feedback learning by listening to human talking and singing voices. The acquired voices were evaluated by listening experiments

A mechanical model of the human vocal system is being developed based on a mechatronics technology under a feedback control. While various ways of vocal sound production have been actively studied so far, a mechanical construction of the vocal system is considered to advantageously realize natural vocalization with its fluid dynamics. Motors are employed for the manipulation of the mechanical system. The system is able to adoptively learn the relations between motor control parameters and the produced vocal sounds using an auditory feedback with neural networks, by mimicking a human vocalization. This paper presents the construction of a talking robot and its singing performance, together with the adaptive control for the pitch learning. The talking robot generates vowel and consonant sounds of different pitches by dynamically controlling the vocal cords, vocal tract and nasal cavity.

In order to support multimedia communication over high speed networks, it is necessary to develop routing algorithms which use for routing more than one QoS parameter. This is because new services such as video on demand and remote meeting systems require better QoS. However, the problem of QoS routing is difficult and to find a feasible route with two independent path constraints is NP-complete. Therefore, QoS routing algorithms for high speed networks must be adaptive, flexible, and intelligent for efficient network management. In a previous work, we proposed a genetic algorithm (GA) based routing method. This method used only the delay time as a routing parameter. In this paper we improve the previous work in three aspects. The new QoS routing method uses two QoS parameters for routing. We implemented a new tree generating algorithm which generates and reduces the tree automatically. Furthermore, we carried out the simulations for different kinds of networks. The simulation results show that the proposed method has a better performance than a conventional GA based routing algorithm.

We are developing a mechanical model of a human vocal system based on a mechatronics technology. Although various ways of vocal sound production have been actively studied so far, a mechanical construction is considered to advantageously realize natural vocalization with its fluid dynamics. In the voice generation, the analysis of the behaviors of the vocal cords and the vocal tract are required to be employed in the mechanical system. Furthermore, the fluid mechanics is less stable to make the control difficult. Several motors are employed to manipulate the mechanical vocal system. A neural network works to establish the relations between motor positions and the produced vocal sounds by an auditory feedback in the learning phase. In the speech performance, the mechanical system is able to utter while vocal pitches and phonemes are adaptively controlled by an auditory feedback control. This paper presents the construction of a vocal tract part and its adaptive control by the neural networks.