• Journal of Korea Multimedia Society
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• v.14 no.1
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• pp.133-143
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• 2011

This paper proposes a mobile navigation system which haptically presents the way to go to visually impaired persons. In order to convey the tactile information to the visually impaired persons, we develop a new tactile module with a solenoid, a permanent magnet and an elastic spring. Furthermore, we suggest 2D vibration flow which originates from one point and gradually propagates to other points on a surface of the haptic navigation system. The tactile module and the vibration flow method are incorporated into the proposed haptic navigation system and they stimulate the user's finger pad and palm, respectively. We conduct experiments to investigate that the proposed navigation system haptically provides the direction to the users. From the experimental results, we verify that the proposed system can generate enough tactile sensation to guide the direction to go in real-time.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.1
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• pp.148-156
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• 2011

This paper presents an implementation of autonomous navigation of a mobile robot indoors. It explains methods for map building, localization, obstacle avoidance and path planning. Geometric map is used for localization and path planning. The localization method calculates sensor data based on the map for comparison with the real sensor data. Monte Carlo Localization(MCL) method is adopted for estimation of the robot position. For obstacle avoidance, an artificial potential field generates repulsive and attractive force to the robot. Dijkstra algorithm plans the shortest distance path from a start position to a goal point. The methods integrate into autonomous navigation method and implemented for indoor navigation. The experiments show that the proposed method works well for safe autonomous navigation.

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.810-815
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• 2013

In case Wi-Fi network based First responder's position tracking system is used, range measurement must be generated from RSSI finger print database. However, it is impossible to build up finger print database and to perform rescue operation at same time in the scene of rescue. In this paper, improvised Wi-Fi network without finger print database and pedestrian dead reckoning based first responders tracking system is proposed.

• The Journal of Korea Robotics Society
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• v.17 no.1
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• pp.8-15
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• 2022

In this paper, we proposed the method of virtual reality-based surgical navigation to reproduce the pre-planned position and angle of the pedicle screw in spinal fusion surgery. The goal of the proposed method is to quantitatively save the surgical plan by applying a virtual guide coordinate system and reproduce it in the surgical process through virtual reality. In the surgical planning step, the insertion position and angle of the pedicle screw are planned and stored based on the virtual guide coordinate system. To implement the virtual reality-based surgical navigation, a vision tracking system is applied to set the patient coordinate system and paired point-based patient-to-image registration is performed. In the surgical navigation step, the surgical plan is reproduced by quantitatively visualizing the pre-planned insertion position and angle of the pedicle screw using a virtual guide coordinate system. We conducted phantom experiment to verify the error between the surgical plan and the surgical navigation, the experimental result showed that target registration error was average 1.47 ± 0.64 mm when using the proposed method. We believe that our method can be used to accurately reproduce a pre-established surgical plan in spinal fusion surgery.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.3
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• pp.181-189
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• 2022

The public open signals from Global Navigation Satellite System (GNSS) including Global positioning system (GPS) are used widely by many peoples in the world except for the public regulated restriction signals which are encrypted. Nowadays there are growing concerns about GNSS signal spoofing which can deceive the GNSS receivers by abusing these open services. To counter these spoofing threats, many researches have been studied including array antenna techniques which can detect the direction of arrival by means of Multiple Signal Classification (MUSIC) algorithm. Originally the array antenna techniques were developed to countermeasure the jamming signal in electronic warfare by using the nulling or beamforming algorithm toward a certain direction. In this paper, we study the anti-spoofing techniques using array antenna to overcome the jamming and spoofing issues simultaneously. First, we will present the theoretical analysis results of spoofing signal response of Minimum Variance Distortionless Response (MVDR) algorithm in array antenna. Then the eigenvector algorithm of covariance matrix is suggested and verified to work with the existing anti-jamming method. The modeling and simulation are used to verify the effectiveness of the anti-spoofing algorithm. Also, the field test results show that the array antenna system with the proposed algorithms can perform the anti-spoofing function. This anti-spoofing method using array antenna is very effective in the view point of solving both the jamming and spoofing problems using the same array antenna hardware.

• Journal of Advanced Navigation Technology
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• v.28 no.4
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• pp.428-435
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• 2024

In this paper, a human activity regeneration (HAR) system based on multiple input multiple output frequency modulation continuous wave (MIMO FMCW) radar was designed and implemented. Using point cloud data from MIMO radar sensors has advantages in terms of privacy, safety, and accuracy. For the implementation of the HAR system, a customized neural network based on PointPillars and depthwise separate convolutional neural network (DS-CNN) was developed. By processing high-resolution point cloud data through a lightweight network, high accuracy and efficiency were achieved. As a result, the accuracy of 98.27% and the computational complexity of 11.27M multiply-accumulates (Macs) were achieved. In addition, the developed neural network model was implemented on Raspberry-Pi embedded system and it was confirmed that point cloud data can be processed at a speed of up to 8 fps.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.1
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• pp.124-131
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• 2005

This paper suggests LOS(Line-Of-Sight) guidance system of a surface vessel in straight-line navigation under ocean currents An LOS vector from the vessel to a point on the path between two way-points is decided and a heading angle is calculated to converge to follow the desired path based on the LOS vector This guidance system is called LOS guidance system. The suggested LOS guidance law has parameters to be properly chosen according to navigational environment. Parameters of LOS guidance system are optimized to reduce propulsive energy and/or position error between desired Position and present position of a ship using genetic algorithm which is a strong optimization algorithm with adaptational random search The effectiveness of the suggested LOS guidance system is assured through computer simulations.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.2
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• pp.13-20
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• 2009

The most of navigation services these days, are designed in order to just provide a shortest path from current position to destination for a user. Several navigation services provides not only the path but some fragmentary information about its point, but, the data tends to be highly restricted because it's quality and quantity totally depends on service provider's providing policy. In this paper, we describe the folksonomy POI(Point of interest) recommender system using mashup in order to provide the information that is more useful to the user. The POI recommender system mashes-up the user's folksonomy data that stacked by user with using external folksonomy service(like Flickr) with others' in order to provide more useful information for the user. POI recommender system recommends others' tag data that is evaluated with the user folksonomy similarity. Using folksonomy mahup makes the services can provide more information that is applied the users' karma. By this, we show how to deal with the data's restrictions of quality and quantity.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.11-14
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• 2003

In this paper, we use Fuzzy Logic and Potential field method for optimal path planning of an autonomous mobile robot and apply to navigation for real-time mobile robot in 2D dynamic environment. For safe navigation of the robot, we use both Global and Local path planning. Global path planning is computed off-line using sell-decomposition and Dijkstra algorithm and Local path planning is computed on-line with sensor information using potential field method and Fuzzy Logic. We can get gravitation between two feature points and repulsive force between obstacle and robot through potential field. It is described as a summation of the result of repulsive force between obstacle and robot which is considered as an input through Fuzzy Logic and gravitation to a feature point. With this force, the robot fan get to desired target point safely and fast avoiding obstacles. We Implemented the proposed algorithm with Pioneer-DXE robot in this paper.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.06a
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• pp.343-345
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• 2014

실시간 위치 기반 선박 충돌 위험도는 자선의 관점에서 선박충돌의 위험을 판단하는 것이 아니라 VTS(Vessel Traffic Service)의 관점에서 충돌 위험이 있는 선박을 식별하고 충돌 위험 지역을 전자 해도에서 실시간으로 확인하여 해당 해역 전체의 선박 교통흐름과 통항하는 선박간의 위험도를 평가하는 것이 목적이다. 항해사로써의 승선 경험과 관제사로써의 근무 경험, 그리고 다 년간 VTS 관제 업무를 수행하고 있는 관제사들로부터 충돌의 위험이 있는 선박을 식별하는 방법으로 주로 선박간의 벡터(코스와 속력)를 실시간으로 모니터링하여 충돌 위험이 있는 선박에게 피항 조치를 취하도록 정보를 제공하는 것으로 확인되었다. 따라서 DCPA(Distance to Closest Point of Approach)와 TCPA(Time to Closest Point of Approach), 그리고 최근접시간을 변수로 하는 충돌 위험 함수식(최대값=100)을 연구하여 각 지점의 위험도를 실시간으로 표시하는 기초 모델을 연구하였다.