• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2016.05a
• /
• pp.352-354
• /
• 2016

Recent with the progress of smart devices, there is an increasing demand for indoor location-based services. For this reason, research on indoor positioning system using a iBeacon techniques added to BLE(Bluetooth Low Energy) specifications of Bluetooth4.0 has been actively. However, RSSI signal used for the measurement of the distance between the iBeacon and the receiving terminal has the problems of inaccurate distance measurement to environmental factors such as obstacles. In this paper, we propose an implemented indoor positioning technique to use filtering technology enhance the reliability of the RSSI signal and the broadcasting signal of the terminal access point function.

• Journal of Broadcast Engineering
• /
• v.27 no.1
• /
• pp.91-103
• /
• 2022

Determination of sound source characteristics such as: sound volume, direction and distance to the source is one of the important techniques for unmanned systems like autonomous vehicles, robot systems and AI speakers. There are multiple methods of determining the direction and distance to the sound source, e.g., using a radar, a rider, an ultrasonic wave and a RF signal with a sound. These methods require the transmission of signals and cannot accurately identify sound sources generated in the obstructed region due to obstacles. In this paper, we have implemented and evaluated a method of detecting and identifying the sound in the audible frequency band by a method of recognizing the volume, direction, and distance to the sound source that is generated in the periphery including the invisible region. A cross-shaped based sound source recognition algorithm, which is mainly used for identifying a sound source, can measure the volume and locate the direction of the sound source, but the method has a problem with "blind spots". In addition, a serious limitation for this type of algorithm is lack of capability to determine the distance to the sound source. In order to overcome the limitations of this existing method, we propose a QRAS-based algorithm that uses rectangular-shaped technology. This method can determine the volume, direction, and distance to the sound source, which is an improvement over the cross-shaped based algorithm. The QRAS-based algorithm for the OSSD uses 6 AITDs derived from four microphones which are deployed in a rectangular-shaped configuration. The QRAS-based algorithm can solve existing problems of the cross-shaped based algorithms like blind spots, and it can determine the distance to the sound source. Experiments have demonstrated that the proposed QRAS-based algorithm for OSSD can reliably determine sound volume along with direction and distance to the sound source, which avoiding blind spots.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.13 no.6
• /
• pp.686-691
• /
• 2003

In the paper, an intelligent biped walking robot that can overcome the obstacle is developed. Walking algorithms are designed based on the analysis of the human's manner of walking. Infrared sensors are used to detect the obstacles in the working environment and the remote controller of the biped robot use a RF module. The experiment results show that the developed biped walking robot can perform the stable static walking, attention walking, rotation and side stepping to avoid the obstacle, and hurdling the obstacle using the distance correction algorithm that is designed based on the distance information between the biped robot and the obstacle.

• Journal of Advanced Navigation Technology
• /
• v.26 no.6
• /
• pp.427-433
• /
• 2022

Obstacle detection, collision recognition, and avoidance technologies are required the collision avoidance technology for UAVs. In this paper, considering collinear multiple static obstacle, we propose an obstacle detection algorithm using LiDAR and a collision recognition and avoidance algorithm based on CPA. Preprocessing is performed to remove the ground from the LiDAR measurement data before obstacle detection. And we detect and classify obstacles in the preprocessed data using the K-means clustering algorithm. Also, we estimate the absolute positions of detected obstacles using relative navigation and correct the estimated positions using a low-pass filter. For collision avoidance with the detected multiple static obstacle, we use a collision recognition and avoidance algorithm based on CPA. Information of obstacles to be avoided is updated using distance between each obstacle, and collision recognition and avoidance are performed through the updated obstacles information. Finally, through obstacle location estimation, collision recognition, and collision avoidance result analysis in the Gazebo simulation environment, we verified that collision avoidance is performed successfully.

• Smart Structures and Systems
• /
• v.15 no.4
• /
• pp.1063-1083
• /
• 2015

The main purpose of this research is to utilize simple mathematical models to depict the vibration behavior and the resulted sound field of a piezoelectric disk for ultrasonic transducers. Instead of using 1-D vibration model, coupled effect between the thickness and the radial motions was considered to be close to the real vibration behavior. Moreover, Huygens-Fresnel principle was used in both incident and reflected waves to analyze the sound field under obstacles in finite distance. Results of the tested piezoelectric disk show that, discrepancies between the simulation and experiment are 2.5% for resonant frequency and 12% for resulted sound field. Therefore, the proposed method can be used to reduce the complexity in modeling vibration problems, and increase the reliability on analyzing piezoeletric transducers in the design stage.

• Proceedings of the KSR Conference
• /
• 2007.11a
• /
• pp.1846-1851
• /
• 2007

According to the Railroad Safety Act and section 42 of the Enforcement Ordinance, railway operators should conduct railway safety training regularly(6 or 3 hours per three months). But Overall Railroad Safety Audit conducted 2006 pointed out nonfulfillment of a regulations on railway worker's safety training to each of every 4 railway operators, which proved that the training management had not carried out properly. E-learning is used in various fields with development of Internet and IT technologies. It might be a good alternative tool for railway workers who is in shift working of the company 24 hours a day. Because it is difficult to collect those employees for training, e-learning could overcome obstacles of time and distance. In order to find out suitable e-learning model to railway sector, e-learning system for railway safety training has been researched through investigating e-learning technology and present railway safety training condition.

• ETRI Journal
• /
• v.40 no.2
• /
• pp.246-256
• /
• 2018

A spatial augmented reality (SAR) system enables a virtual image to be projected onto the surface of a real-world object and the user to intuitively control the image using a tangible interface. However, occlusions frequently occur, such as a sudden change in the lighting environment or the generation of obstacles. We propose a robust object tracker based on a multithreaded system, which can track an object robustly through occlusions. Our multithreaded tracker is divided into two threads: the detection thread detects distinctive features in a frame-to-frame manner, and the tracking thread tracks features periodically using an optical-flow-based tracking method. Consequently, although the speed of the detection thread is considerably slow, we achieve real-time performance owing to the multithreaded configuration. Moreover, the proposed outlier filtering automatically updates a random sample consensus distance threshold for eliminating outliers according to environmental changes. Experimental results show that our approach tracks an object robustly in real-time in an SAR environment where there are frequent occlusions occurring from augmented projection images.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.737-741
• /
• 2004

A mobile robot system is developed which is remotely controlled by a haptic master called ‘PHANTOM’. The mobile robot has 4 ultrasonic sensors and single CCD camera which detects the distance from a mobile robot to obstacles in the environment and sends this information to a haptic master. For more convenient remote control, haptic rendering process is performed like viscosity forces and obstacle avoidance forces. In order to show the effectiveness of the developed system, we experiment that the mobile robot runs through the maze and the time is checked to complete the path of the maze with/without the haptic information. Through this repeated experiments, haptic information proves to be useful for remote control of a mobile robot.

• Journal of information and communication convergence engineering
• /
• v.14 no.2
• /
• pp.129-135
• /
• 2016

In this paper, we present a novel algorithm for image-based maritime obstacle detection using global sparsity potentials (GSPs), in which "global" refers to the entire sea area. The horizon line is detected first to segment the sea area as the region of interest (ROI). Considering the geometric relationship between the camera and the sea surface, variable-size image windows are adopted to sample patches in the ROI. Then, each patch is represented by its texture feature, and its average distance to all the other patches is taken as the value of its GSP. Thereafter, patches with a smaller GSP are clustered as the sea surface, and patches with a higher GSP are taken as the obstacle candidates. Finally, the candidates far from the mean feature of the sea surface are selected and aggregated as the obstacles. Experimental results verify that the proposed approach is highly accurate as compared to other methods, such as the traditional feature space reclustering method and a state-of-the-art saliency detection method.

• International Journal of Quality Innovation
• /
• v.10 no.2
• /
• pp.57-76
• /
• 2009

Although many adherents openly praise the importance of quality management practices (QMP) in organisations, others have identified significant costs and implementation obstacles. Some recent studies showed that QMP have failed due to the ignorance of quality cultures. How to improve the success rate of QMP in organisations has become a critical issue both in the academy and in practice. This paper discusses the common enablers of and cultural impacts on QMP. It explores the dimensions of national versus organisational culture, and identifies the main features of four quality culture models as advocated in the literature in relation to facilitating QMP in organisations. It was found that flat structures, decentralised functions, empowerment, flexibility, innovation, limited rules and regulations and teamwork favor the QMP implementation. For facilitating culture changes for QMP, values associated with low power distance, low uncertainty avoidance and collectivism would have to be nurtured. Further research is needed to incorporate the findings and develop a practical quality culture approach for real applications in industry.