• 한국멀티미디어학회논문지
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• 제20권2호
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• pp.371-381
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• 2017

The performance of the statistical context-sensitive spelling error correction depends on the quality and quantity of the data for statistical language model. In general, the size and quality of data in a statistical language model are proportional. However, as the amount of data increases, the processing speed becomes slower and storage space also takes up a lot. We suggest the improved statistical language model to solve this problem. And we propose an effective spelling error candidate generation method based on a new statistical language model. The proposed statistical model and the correction method based on it improve the performance of the spelling error correction and processing speed.

• 정보관리연구
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• 제21권1호
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• pp.76-92
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• 1990

본고(本稿)는 서지(書誌) 데이터베이스제작(製作)과 정보검색관점(情報檢索觀點)에서 자동철자교정(自動綴字校正)에 대(對)하여 논(論)한다. 여기에는 흔히 발견되는 철자오류(綴字誤謬)의 유형(類型)과 서지(書誌) 데이터베이스내(內)의 철자오류(綴字誤謬)가 미치는 영향(影響)에 대하여 기술(記述)하고 있으며, 자동철자교정(自動綴字校正)시스템의 일반적 구성에 관해서는 문서(文書)의 정규화, 철자검증(綴字檢證), 철자교정(綴字校正), 사용자(使用者) 인터페이스로 나누어 기술(記述)하고 있다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.537-540
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• 2003

In this paper, we evaluated error correction performance and recording density of an optical disc system. The performance of Low-Density Parity Check code (LDPC) is compared to the HD-DVD (BD) ECC. The recording density of optical disc can be increased by reducing the redundancy of the user data. Moreover, since the correction capability of LDPC with decreased redundancy is better than that of BD, the recording density can also be increased by reducing the mark length of the data on the disc surface.

• 산업기술연구
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• 제18권
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• pp.17-25
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• 1998

Recently, there are a lot of studies to use a satellite image data in order to investigate a simultaneous change of a wide range area as a lake. However, many cases of a water quality research occur as problem when we try to extract the water quality factors from the satellite image data, because of the atmosphere scattering exert as bad influence on a result of analysis. In this study, and attempt was made to select the relative atmospheric correction method for the water quality factors extraction from the satellite image data. And also, the time-series analysis of the water quality factors extraction from the satellite image data. And also, the time-series analysis of the water quality factors was performed by using the multi-temporal image data.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.478-481
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• 2005

The PMU (Payload Management Unit) is the main subsystem for the management, control and power supply of the MSC (Multi-Spectral Camera) Payload operation. It is the most important function for the electro-optical camera system that performs the Non-Uniformity Correction (NUC) function of the raw imagery data, rearranges the data from the CCD (Charge Coupled Device) detector and output it to the Data Compression and Storage Unit (DCSU). The NUC board in PMU performs it. In this paper, the NUC board system is described in terms of the configuration and the function, the efficiency for non-uniformity correction, and the influence of the data compression upon the peculiar feature of the CCD pixel. The NUC board is an image-processing unit within the PMU that receives video data from the CEV (Camera Electronic Unit) boards via a hotlinkand performs non-uniformity corrections upon the pixels according to commands received from the SBC (Single Board Computer) in the PMU. The lossy compression in DCSU needs the NUC in on-orbit condition.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.159-159
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• 2023

The Amazon River basin is one of the largest basins in the world, and its ecosystem is vital for biodiversity, hydrology, and climate regulation. Thus, understanding the hydrometeorological process is essential to the maintenance of the Amazon River basin. However, it is still tricky to monitor the Amazon River basin because of its size and the low density of the monitoring gauge network. To solve those issues, remote sensing products have been largely used. Yet, those products have some limitations. Therefore, this study aims to do bias corrections to improve the accuracy of Satellite Precipitation Products (SPPs) in the Amazon River basin. We use 331 rainfall stations for the observed data and two daily satellite precipitation gridded datasets (CHIRPS, TRMM). Due to the limitation of the observed data, the period of analysis was set from 1st January 1990 to 31st December 2010. The observed data were interpolated to have the same resolution as the SPPs data using the IDW method. For bias correction, we use convolution neural networks (CNN) combined with an autoencoder architecture (ConvAE). To evaluate the bias correction performance, we used some statistical indicators such as NSE, RMSE, and MAD. Hence, those results can increase the quality of precipitation data in the Amazon River basin, improving its monitoring and management.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2020년도 학술발표회
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• pp.166-166
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• 2020

Recently, As the frequency of localized heavy rains increases, the use of high-resolution radar data is increasing. The produced radar rainfall has still gaps of spatial and temporal compared to gauge observation rainfall, and in many studies, various statistical techniques are performed for correct rainfall. In this study, the precipitation correction of the S-band Dual Polarization radar in use in the flood forecast was performed using the ConvAE algorithm, one of the Convolutional Neural Network. The ConvAE model was trained based on radar data sets having a 10-min temporal resolution: radar rainfall data, gauge rainfall data for 790minutes(July 2017 in Cheongju flood event). As a result of the validation of corrected radar rainfall were reduced gaps compared to gauge rainfall and the spatial correction was also performed. Therefore, it is judged that the corrected radar rainfall using ConvAE will increase the reliability of the gridded rainfall data used in various physically-based distributed hydrodynamic models.

• 대한임베디드공학회논문지
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• 제15권4호
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• pp.159-166
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• 2020

The IBC (Intra-Body Communication) benefits from a wireless communication system for exchanging various kinds of digital information through wearable electronic devices and sensors. The IBC using the human body as the transmission channel allows wireless communication without the transmitting radio frequency waves to the air. This paper discusses the results of experiments on electrostatic coupling IBC based on FSK (Frequency Shift Keying) and 1 bit error correction. We implemented FSK communication and 1 bit error correction algorithm using the MCU boards and aluminum tape electrodes. The transmitter modulates digital data using 50% duty square wave as carrier signal and transmits data through human body. The receiver performs ADC (Analog to Digital Conversion) on carrier signal from human body. In order to figure out the frequency of carrier signal from ADC results, we applied zero-crossing algorithm which is used to detect the edge characteristic in computer vision. Experiment results shows that digital data modulated as square wave can be successfully transmitted through human body by applying the proposed architecture of a 1ch GPIO as a transmitter and 1ch ADC for as a receiver. Also, this paper proposes 1 bit error correction technique for reliable IBC. This technique performs error correction by utilizing the feature that carrier signal has 50% duty ratio. When 1 bit error correction technique is applied, the byte error rate at receiver side is improved around 3.5% compared to that not applied.

• 한국지구과학회지
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• 제28권7호
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• pp.825-837
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• 2007

한국 국립해양조사원의 수심자료와 미국 NIMA((National Imagery and Happing Agency)의 수치지형자료를 바탕으로 우리나라 일원에서 측정한 중력의 지형보정을 위한 위도 및 경도 간격이 각각 $3"{\times}3"$)인 지형자료를 재편집하였다. 이 자료를 바탕으로 지구 곡률을 고려한 정밀 지형보정값을 계산하기 위한 알고리즘을 개발하였고, 중력측정점으로부터 반지름 166.735 km인 원 내부에 대한 지형보정값을 계산하는 Fortran프로그램을 작성하였다. 이 알고리즘 및 프로그램을 이용하여 남한 전역에 대한 지형보정값을 계산하였다. 그 결과 최대값은 56.508 mGal 이고 평균값은 4.539 mGU이다.

• 한국지리정보학회지
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• 제6권1호
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• pp.98-106
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• 2003

위성영상의 장점인 고해상도, 다분광, 주기성, 광범위 촬영 등에 의해 위성영상은 초창기의 군사, 환경 분야의 적용을 뛰어넘어 현재는 많은 활용 분야에 널리 적용되고 있다. 이러한 위성영상을 효율적으로 활용하기 위해서는 여러가지 영상처리를 하여야 하며, 특히 기하보정 영상처리는 모든 활용분야에 있어 꼭 필수적인 단계이다. 따라서 본 연구에서는 이러한 기하보정 작업을 용이하게 하기 위하여 LANDSAT 위성영상을 중심으로 크게 세 가지 작업을 수행하여 기하보정 데이터를 구축하였다. 첫번째는 한반도 지역에 대하여 기하보정에 필요한 지상기준점을 선정하여 데이터베이스를 구축하였다. 두번째는 구축된 지상기준점을 이용하여 연도별로 구분된 LANDSAT 위성영상에 대하여 기하보정을 수행하였고, 마지막으로는 기하보정된 영상을 한반도 지역을 대상으로 모자이크 하였다. 이와 같은 작업을 통하여 576개의 지상기준점, 165장의 기하보정된 영상과 7장의 한반도 모자이크 영상을 구축하였다. 구축된 한반도의 기하보정 데이터는 많은 분야에 기초자료로 활용되리라 기대한다.