• Journal of Sensor Science and Technology
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• v.31 no.1
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• pp.64-68
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• 2022

Herein, we propose a LoRaWAN-based small draft system that can measure the ocean current flow (speed, direction, and distance) in real time at the request of the Coast Guard to develop a device that can promptly find survivors at sea. This system has been implemented and verified in the early stages of rescue after maritime vessel accidents, which are frequent. GPS signals often transmit considerable errors, so correction algorithms using the improved triangulation method algorithm are required to accurately indicate the direction of currents in real time. This paper is structured in the following manner. The introduction section elucidates rescue activities in the case of a maritime accident. Chapter 2 explains the characteristics and main parameters of the GPS surveying technique and LoRaWAN communication, which are related studies. It explains and expands on the critical distance error correction algorithm for GPS signals and its improvement. Chapter 3 discusses the design and analysis of small draft buoys. Chapter 4 presents the testing and validation of the implemented system in both onshore and offshore environments. Finally, Section 5 concludes the study with the expected impact and effects in the future.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.285-289
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• 1999

A processing system to produce cloud-free composite image data set was developed. In the process, a fine geometric correction based on orbit parameters and ground control points and radiometric correction based on 6S code are applied. Presently, by using AVHRR image data received at Tokyo, Okinawa, Ulaanbaatar and Bangkok, data set of 10 days composite images covering almost whole Asian region.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.799-804
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• 1993

In this paper, the scheme of combining the orbit correction and attitude control of a 3-axis stabilized satellite is suggested. Being coupled and complimentary, it is preferable to achieve the required orbit correction and the desired attitude control simultaneously. A solution of the probes simultaneous control of orbit correction and attitude of a satellite, is obtained by solving the two point boundary value problem numerically. The first-order gradient algorithm is used to solve the numerical problem. The simulation results show that the East-West station keeping process with the combined system of an orbit correction and an attitude control is satisfactory.

• Journal of Cadastre & Land InformatiX
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• v.48 no.2
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• pp.99-108
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• 2018

The purpose of this study is to determine the precise height in mountainous areas of South Korea and Jiri mountain area was selected as a test bed for the study. Gravity observation and GNSS surveying were performed for 44 BM(Benchmark) points in the test bed and calculate the height and the height correction. In the calculation, the dynamic correction amount, the orthometric correction amount and the normal correction amount were calculated, and the dynamic height and orthometric height and the normal height were calculated considering each correction amount. The results showed that the difference between normal gravity and observed gravity and also the difference between orthometric correction and the normal correction. In addition, the results of the comparison of the present official BM height and the computed orthometric height in this study show that Korean height system should be shifted from the normal orthometric height system to the orthometric height system. Because the difference between the orthometric correction and the normal correction within the test bed indicated a distribution of at a minimum of -234.41 mm up to 196.925 mm, and the difference between the present official BM height and the calculated orthometric height were distributed from -0.121m to 0.011 m.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.3
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• pp.100-109
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• 2022

In this study, calibration technology that increases the alignment accuracy in large flexible flat panels was studied. For precise of calibration, a systematization of the calibration algorithm was established, and a calibration correction technique was studied to revise calibration errors. A coordinate systems of camera and UVW stage was established to get the global position of the mark, and equations for translational and rotational calibration were systematically derived based on geometrical analysis. Correction process for the calibration data was carried, and alignment experiments were performed sequentially in cases of the presence or absence of calibration-correction. Alignment results of both calibration correction and non-calibration correction showed accuracy performance less than 1㎛. On the other hand, the standard deviation in calibration-correction is smaller than non-calibration correction. Therefore, calibration correction showed improvement of the alignment repeatability.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.1
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• pp.76-82
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• 2000

An arc sensor system to compensate positional errors was developed on the foundation of sensor interface system to make use of the on-line shift function of industrial welding robot. Investigating the on-line shift function, we examine the quantitative relationship between the deviation from programmed path and the correction data transferred from personal computer to robot controller. The number of input parameters for weld seam tracking can be reduced by making the relationship between the deviation and the correction data during half weaving be the function of only cross time. With the results of weld seam tracking for the butt joint with V-groove and fillet joint of sheet metal, good performance was implemented. By developing the sensor interface system to compensate the positional errors, industrial welding robot can be expected to contribute to the promotion of welding automation.

• Journal of the Korea Society of Computer and Information
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• v.15 no.7
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• pp.83-90
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• 2010

In vocabulary recognition system has reduce recognition rate unrecognized error cause of similar phoneme recognition and due to provided inaccurate vocabulary. Input of inaccurate vocabulary by feature extraction case of recognition by appear result of unrecognized or similar phoneme recognized. Also can't feature extraction properly when phoneme recognition is similar phoneme recognition. In this paper propose vocabulary recognition post-process error correction system using phoneme likelihood based on phoneme feature. Phoneme likelihood is monophone training phoneme data by find out using MFCC and LPC feature extraction method. Similar phoneme is induced able to recognition of accurate phoneme due to inaccurate vocabulary provided unrecognized reduced error rate. Find out error correction using phoneme likelihood and confidence when vocabulary recognition perform error correction for error proved vocabulary. System performance comparison as a result of recognition improve represent MFCC 7.5%, LPC 5.3% by system using error pattern and system using semantic.

• Journal of Power Electronics
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• v.6 no.2
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• pp.121-130
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• 2006

This paper presents the performance and efficiency of a drive system incorporating a switched-reluctance motor (SRM) with input power factor correction (PFC). The proposed system consists of a PFC, bi-directional converter, an inverter, and a SRM operating as based voltage source drives (VSD). First, theoretical analysis is made for each identified mode of operation in the drive system. This is followed by comparing the performance of the SRM drive system with and without a PFC circuit. The losses are also calculated for both systems and overall efficiency. Experimental results are presented to prove the theoretical analysis.

• Journal of the Semiconductor & Display Technology
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• v.19 no.3
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• pp.112-117
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• 2020

NAND flash memory is a non-volatile memory that retains stored data even without power supply. Internal memory used as a data storage device and solid-state drive (SSD) is used in portable devices such as smartphones and digital cameras. However, NAND flash memory carries the risk of electric shock, which can cause errors during read/write operations, so use error correction codes to ensure reliability. It efficiently recovers bad block information, which is a defect in NAND flash memory. BBT (Bad Block Table) is configured to manage data to increase stability, and as a result of experimenting with the error correction code algorithm, the bit error rate per page unit of 4Mbytes memory was on average 0ppm, and 100ppm without error correction code. Through the error correction code algorithm, data stability and reliability can be improved.

• Earthquakes and Structures
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• v.13 no.1
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• pp.17-27
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• 2017

In this study, the characteristics of site amplification at seismic observation stations in Japan were estimated using the attenuation relationship of each station's response spectrum. Ground motion records observed after 32 earthquakes were employed to construct the attenuation relationship. The station correction factor at each KiK-net station was compared to the transfer functions between the base rock and the surface. For each station, the plot of the station correction factor versus the period was similar in shape to the graphs of the transfer function (amplitude ratio versus period). Therefore, the station correction factors are effective for evaluating site amplifications considering the period of ground shaking. In addition, the station correction factors were evaluated with respect to the average shear wave velocities using a geographic information system (GIS) dataset. Lastly, the site amplifications for specific periods were estimated throughout Japan.