• Applied Biological Chemistry
• /
• v.41 no.8
• /
• pp.583-586
• /
• 1998

Porous ceramic cups are used for monitoring ion concentration in soil solutions in various time course and depth. A soil solution sampler was constructed in laboratory by inserting pliable perfluoroalkoxy(PFA) tubings into porous cup through holes in PVC rod segment which plugged top opening of the porous cup. The system was installed in drip irrigated soil in a vertical position, and nitrogen movement below the drip basin was monitored. To collect soil solution, vacuum in the cup was applied with a hand vacuum pump. The samples obtained were sufficient enough to run quantitative analyses for a number of chemicals. Nitrogen transformation and movement could be well defined, and the system seemed to be relevant to the other soil solution samplers in monitoring chemical movement in soil. Although this system has general deficiencies found in the other samplers using ceramic cup, it could be easily constructed at a low cost. Since the tubing was pliable, the cups could be installed in horizontal position, and this allows installations of the cups at more precise depth increments and also more precise samplings of soil solution at each depth.

• Journal of Astronomy and Space Sciences
• /
• v.29 no.3
• /
• pp.269-274
• /
• 2012

Kinematic global positioning system precise point positioning (GPS PPP) technology is widely used to the several area such as monitoring of crustal movement and precise orbit determination (POD) using the dual-frequency GPS observations. In this study we developed a kinematic PPP technology and applied 3-pass (forward/backward/forward) filter for the stabilization of the initial state of the parameters to be estimated. For verification of results, we obtained GPS data sets from six international GPS reference stations (ALGO, AMC2, BJFS, GRAZ, IENG and TSKB) and processed in daily basis by using the developed software. As a result, the mean position errors by kinematic PPP showed 0.51 cm in the east-west direction, 0.31 cm in the north-south direction and 1.02 cm in the up-down direction. The root mean square values produced from them were 1.59 cm for the east-west component, 1.26 cm for the south-west component and 2.95 cm for the up-down component.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.12
• /
• pp.21-26
• /
• 2019

This paper constructs a real-time monitoring system that can identify the individual positions of infants and their proximity to other infants using an Internet of Things (IoT)-based nameplate. The system consists of a precision location tracking module, a data transmission system for calculating gateway location information, a service platform server, and a data analysis processing module considering the development of infants and young children. The purpose of this study is to extract information about how infants interact with each other. The information gathered through this system can be used as important information to improve the peer relations of all infants and toddlers, from neglected infants to infants with no social development problems, to more popular infants. It is possible, based on the proximity information between infants and toddlers, that the teacher can identify positive interactions or negative interactions, and can educate infants on how to improve their peer relationships. These results can be used for consultation with parents, and the information collected through this system can be used as a database to establish a system for improving the relationships between infants and toddlers.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.2
• /
• pp.286-293
• /
• 2008

The design and implementation of a personal navigation system including activity monitoring function is given in this paper. The system consists of a 3 dimensional MEMS accelerometer, digital compasses and ZigBee communication. An accelerometer and digital compasses are used to compute the position and activity. The obtained position and activity information is transmitted to a fixed beacon via ZigBee. At the same time, activity information is stored in the personal navigation system to a batch analysis program. The step detection algorithm which is robust to attaching location is proposed. Also two digital compass error compensation algorithms are proposed to find more precise headings. The experiments with a real system show that the activities of users and continuous locations less than 1.5m errors are obtained after 80m walking.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.19 no.5
• /
• pp.1055-1062
• /
• 2015

A GPS based wave height meter system is proposed in this paper. The proposed system uses a dual-frequency measurements, a precise GPS satellite information and a PPP-based navigation algorithm to estimate the position with high accuracy. This method does not need to receive corrections from the reference stations. Therefore, unlike RTK based wave meter, regardless of the distance to the reference stations, it is possible to estimate position with high accuracy. This system is very simple and accurate system, but accelerometer-based system requires the other sensors such as GPS. Because position error is accumulated in the accelerometer system and must be removed periodically for high accuracy. In order to get the measurements and test the proposed wave height meter system, a buoy equipped with the test platform is installed on the sea near by Jukbyeon habor in Uljin, Korea. Then, to evaluate the performance, compares built-in commercial wave height meter with proposed system.

• Journal of Astronomy and Space Sciences
• /
• v.28 no.3
• /
• pp.217-223
• /
• 2011

Precise point positioning (PPP) is increasingly used in several parts such as monitoring of crustal movement and maintaining an international terrestrial reference frame using global positioning system (GPS) measurements. An accuracy of PPP data processing has been increased due to the use of the more precise satellite orbit/clock products. In this study we developed PPP algorithm that utilizes data collected by a GPS receiver. The measurement error modelling including the tropospheric error and the tidal model in data processing was considered to improve the positioning accuracy. The extended Kalman filter has been also employed to estimate the state parameters such as positioning information and float ambiguities. For the verification, we compared our results to other of International GNSS Service analysis center. As a result, the mean errors of the estimated position on the East-West, North-South and Up-Down direction for the five days were 0.9 cm, 0.32 cm, and 1.14 cm in 95% confidence level.

• Journal of Auto-vehicle Safety Association
• /
• v.12 no.2
• /
• pp.33-39
• /
• 2020

This paper presents an Around View Monitoring (AVM) stop-line detection based longitudinal position correction algorithm for automated driving on urban roads. Poor positioning accuracy of low-cost GPS has many problems for precise path tracking. Therefore, this study aims to improve the longitudinal positioning accuracy of low-cost GPS. The algorithm has three main processes. The first process is a stop-line detection. In this process, the stop-line is detected using Hough Transform from the AVM camera. The second process is a map matching. In the map matching process, to find the corrected vehicle position, the detected line is matched to the stop-line of the HD map using the Iterative Closest Point (ICP) method. Third, longitudinal position of low-cost GPS is updated using a corrected vehicle position with Kalman Filter. The proposed algorithm is implemented in the Robot Operating System (ROS) environment and verified on the actual urban road driving data. Compared to low-cost GPS only, Test results show the longitudinal localization performance was improved.

• Journal of Electrical Engineering and Technology
• /
• v.7 no.5
• /
• pp.797-806
• /
• 2012

Fault detection and isolation (FDI) algorithms provide fault monitoring methods in GPS measurement to isolate abnormal signals from the GPS satellites or the acquired signal in receiver. In order to monitor the occurred faults, FDI generates test statistics and decides the case that is beyond a designed threshold as a fault. For such problem of fault detection and isolation, this paper presents and evaluates position domain integrity monitoring methods by formulating various pseudorange prediction methods and investigating the resulting test statistics. In particular, precise measurements like carrier phase and Doppler rate are employed under the assumption of fault free carrier signal. The presented position domain algorithm contains the following process; first a common pseudorange prediction formula is defined with the proposed variations in pseudorange differential update. Next, a threshold computation is proposed with the test statistics distribution considering the elevation angle. Then, by examining the test statistics, fault detection and isolation is done for each satellite channel. To verify the performance, simulations using the presented fault detection methods are done for an ideal and real fault case, respectively.

• Journal of Advanced Marine Engineering and Technology
• /
• v.33 no.1
• /
• pp.71-80
• /
• 2009

The response characteristics of EHA systems are sensitive to the temperature change of working fluid because the temperature of working fluid causes the variation of system parameters such as effective bulk modulus and viscous friction coefficient. In this paper, a precise position control of EHA system using the adaptive sliding mode control system is suggested. The adapted system parameters such as effective bulk modulus and viscous friction coefficient can be used for monitoring failures in the EHA system which has potential applications in the industrial fields. Not only the accuracy of adapted system parameters but also the improved performance and robustness in a given reference position of the cylinder are verified by computer simulation using AMESim software.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.15 no.2
• /
• pp.71-78
• /
• 2020

This paper proposes vision sensors and deep learning-based around view monitoring system for ship berthing. Ship berthing to the port requires precise relative position and relative speed information between the mooring facility and the ship. For ships of Handysize or higher, the vesselships must be docked with the help of pilots and tugboats. In the case of ships handling dangerous cargo, tug boats push the ship and dock it in the port, using the distance and velocity information receiving from the berthing aid system (BAS). However, the existing BAS is very expensive and there is a limit on the size of the vessel that can be measured. Also, there is a limitation that it is difficult to measure distance and speed when there are obstacles near the port. This paper proposes a relative distance and speed estimation system that can be used as a ship berthing assist system. The proposed system is verified by comparing the performance with the existing laser-based distance and speed measurement system through the field tests at the actual port.