Κυριακή 8 Σεπτεμβρίου 2019

Obstacle avoidance path generation method for mobile robot using varying search range

Abstract

In this study, an obstacle avoidance algorithm, with variable range searching, is proposed for a mobile robot. In the case of the distance transform method, the mobile robot cannot avoid the obstacle when it is narrow. We prepare a grid map with the obstacle and distance levels from a destination. A path with both the least number of turns, and the shortest distance, is generated. The search range depends on the distance between the current position and the obstacle. The algorithm can generate the avoidance path without regard to the shape of the obstacle. In the computer simulation, the proposed algorithm can generate a path that avoids the obstacle. As an experiment, a position detection system used contrast differences, by means of a web camera, to get the coordinates of the mobile robot. It is confirmed that, in the experiment, the mobile robot reached the goal grids without hitting the obstacle.

Implementation of an AR Traditional Japanese Craft Presentation System: presentation of traditional crafts using the Kansei retrieval method

Abstract

The impressions of traditional Japanese crafts retrieved by a presentation system adopting the Kansei method were evaluated in a questionnaire survey. By analyzing the survey results, we associated the visual features of the traditional crafts with the Kansei words. Kansei means sensibility and the ability to accept the impression. In addition, we extracted a feature quantity of the traditional crafts, called the visual pattern image coding, from the traditional craft image, and associated this physical feature with the visual features of the traditional crafts. From these analyses, we implemented an augmented reality (AR) Traditional Japanese Craft Presentation System using the Kansei retrieval method. To evaluate the effectiveness of the Kansei retrieval method, we investigated the satisfaction levels of the retrieved results of traditional crafts. The subjects’ responses to the AR Traditional Japanese Craft Presentation System were overwhelmingly positive.

Effects of emotionally induced language sounds on brain activations for communication

Abstract

Emotions play an important role in human communication. We conducted a study to identify the effect of emotions in language sounds in terms of brain functions. The sounds of Japanese sentences spoken with and without emotion were reversed to eliminate their semantic influence on the subjects’ emotional perception. Three sets of sentences with non-emotional and happy, sad, and angry emotional tones were recorded and reversed. The brain activities of 20 native Japanese speakers in their twenties were monitored by near-infrared spectroscopy (NIRS) while they listened to the reversed Japanese sounds with and without the emotions. Our analysis of the experimental results demonstrated that almost all the brain areas monitored by the NIRS probes were activated more when the subjects listened to emotional language sounds than to non-emotional sounds. In particular, the frontopolar cortex area, which is associated with short-term memory, was significantly activated. Since short-term memory is known to provide important information for communication, these results suggest that emotional aspects of language sounds are essential for successful communication and thus should be implemented in human–robot communication systems.

Analysis of end-plate using multi-channel surface EMG

Abstract

By individually examining the characteristics of conducting waves in multi-channel surface electromyogram (EMG) signals, there is a possibility to understand the mobilization mechanism of muscle contraction. It is important to consider the potential obtained from the surface electromyogram (EMG) signal conducted from a large number of moving units in the muscle, as well as the interference potential due to the conducting action potential. The main purpose of this research paper is to find the exact characteristics of conducting waves close to an end-plate using the antiphase conduction method. To evaluate the position of the end-plate, every conducting wave will be investigated by multi-channel surface EMG, and the formation process for the conducting waves will be analyzed.

Emotional evaluation for pictures displayed with small FOV telescope environment in virtual reality headset

Abstract

We carried out an experiment to examine emotional effect associated with images displayed in small field of view (FOV) telescope like virtual screen environment with VR-HMDs. We manipulate FOV of a virtual camera in VR to change the view of contents. Decreasing FOV makes view of angle narrow, and therefore, the view in VR looks like telescope, in which environment the view greatly moves with even small HMD movement. With smaller value of FOV, the view in VR is more sensitive to HMD movement and requires subjects to keep concentrating not to move their heads to watch target contents properly. Stronger emotional responses were observed with smaller value of FOV in the experiment. The result indicates the possibility of controlling effectiveness of the same contents with the same VR-HMD. This result is expected to improve a wide range of medical usage of VR contents.

HMD-based cover test system for the diagnosis of ocular misalignment

Abstract

The diagnosis of ocular misalignment is difficult and needs examination by ophthalmologists and orthoptists. However, there are not enough qualified personnel to perform such diagnoses. The eye position check is in part systematized. With this check system, we can detect not only the symptoms but also the angle and the extent of strabismus. However, the types of strabismus that can be detected with this technique are limited to exotropia. The purpose of this study is to develop a simplified check system to screen at least the presence of strabismus apart from the type of strabismus or amount of ocular deviation. First, we digitalized the check process. Specifically, we digitized the elemental technology, i.e., the cover–uncover function, required for automation of the typical cover test for eye position check. Furthermore, we developed and implemented an abnormality determination process and evaluated the performance of the system through this experiment, the results of which indicated a higher detection capability than the conventional cover test performed by ophthalmologists and orthoptists.

Long-distance sea wave extraction method based on improved Otsu algorithm

Abstract

Sea wave extraction is the foundation of sea wave measurement, which plays a significant role in binocular stereo vision-based tsunami early-warning systems. However, long-distance sea surface images possess two typical features: ununiformed illuminance and a low signal-to-noise ratio that makes it difficult to extract sea waves out from sea surface images and that leads to incorrect extractions. In this paper, we improved the Otsu algorithm to realize a dynamic multi-threshold algorithm for sea wave extraction. First, the original image was divided into small blocks and the dynamic multi-thresholds were determined according to local sea surface illuminance. Then an evaluation function was defined to add constraint conditions to adjacent blocks’ thresholds. Finally, sea waves were extracted out using the blocks’ thresholds in all the blocks. As seen in our experimental results, the correct extraction rate was 80.9%, most sea waves are extracted regardless of their intensity.

Dynamic hybrid position/force control for the quadrotor with a multi-degree-of-freedom manipulator

Abstract

In the field of aerial robotics, physical interaction with the surrounding environment is currently receiving a considerable attention. One of the key challenges is to control not only the position, but also the force exerted by the end-effector while performing complex tasks such as object manipulation, inspection, and assembly/disassembly. To meet these demands, this paper proposes a dynamic hybrid position/force controller for a quadrotor-borne multi-degree-of-freedom manipulator. The system is modeled under the situation that the constraints on the end-effector are described by a set of hypersurfaces, and system dynamics are then developed while taking into account the redundancy of the system. To verify the effectiveness of the proposed hybrid controller, we carried out numerical simulations for two different application scenarios which include (1) placement of a sensor unit on a vertical wall and (2) inspection with contact on a curved-shape wall. The results show that the system is able to maintain the desired force and position simultaneously in both cases.

Use of access characteristics to distinguish legitimate user traffic from DDoS attack traffic

Abstract

Distributed denial of service attacks are a serious threat in the current information society, where the Internet plays an important role as infrastructure. We have been studying ways to mitigate these attacks using a method that distinguishes between legitimate users and attacks. Our previous method was not sufficient because it only analyzed access logs after the attack. In this study, we propose a new method that can distinguish between legitimate users and attacks while the services are running. When the IDS detects an attack, a quarantine server distinguishes legitimate users using access characteristics. The access characteristics are: (1) user follows links, (2) sender accessed a popular page, and (3) the sender’s current average transmission interval. Our experiments confirmed that the proposed method can distinguish between legitimate users and attacks.

Artificial intelligence, ethics and human values: the cases of military drones and companion robots

Abstract

Can artificial intelligence (AI) be more ethical than human intelligence? Can it respect human values better than a human? This article examines some issues raised by the AI with respect to ethics. The utilitarian approach can be a solution, especially the one that uses agent-based theory. We have chosen two extreme cases: combat drones, vectors of death, and life supporting companion robots. The ethics of AI and unmanned aerial vehicles (UAV) must be studied on the basis of military ethics and human values when fighting. Despite the fact that they are not programmed to hurt humans or harm their dignity, companion robots can potentially endanger their social, moral as well as their physical integrity. An important ethical condition is that companion robots help the nursing staff to take better care of patients while not replacing them.

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