• 한국멀티미디어학회논문지
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• 제25권2호
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• pp.280-286
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• 2022

In order to efficiently collect data, it is essential to locate the facilities and analyze the movement data. The current technology for location collection can collect data using a GPS sensor, but GPS has a strong straightness and low diffraction and reflectance, making it difficult for indoor positioning. In the case of indoor positioning, the location is determined by using wireless network technologies such as Wifi, but there is a problem with low accuracy as the error range reaches 20 to 30 m. In this paper, using BLE 4.2 built in Raspberry Pi, we implement Bluetooth Smart Ready. In detail, a beacon was produced for Advertise, and an experiment was conducted to support the serial port for data transmission/reception. In addition, advertise mode and connection mode were implemented at the same time, and a 3-count gradual algorithm and a quadrangular positioning algorithm were implemented for Bluetooth RSSI error correction. As a result of the experiment, the average error was improved compared to the first correction, and the error rate was also improved compared to before the correction, confirming that the error rate for position measurement was significantly improved.

• 한국콘텐츠학회논문지
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• 제8권10호
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• pp.37-44
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• 2008

논문은 암호문 송신 중 전송 오류에 의한 암복호화의 문제에 대한 해결책을 제시 한다. 블록 암호 알고리즘은 산사태(avalanche) 효과로 인해 단일 비트 오류에 대해서도 많은 비트에 오류를 발생시킨다. 이를 해결하기 위해 재배열 과정과 간단한 오류 정정 코드를 이용해서 산사태(avalanche) 효과에 강인한 방안을 제안한다. 재배열 과정은 간단한 오류 정정 코드를 사용하기 위한 것이다. 재배열 과정은 한 프레임 내에서 전송의 기본 단위인 n-비트 블록 내에 1비트의 단일 오류만이 존재 할 수 있도록 오류를 여러 단위에 분산시키는 역할을 하게 된다. 즉, n-비트 내에서 단일 오류만이 존재하게 되어 단일 오류 정정 코드로 쉽게 복원이 가능하게 된다. 이 방식은 보다 큰 데이터 단위에 확장하여 사용 될 수 있다.

• Current Optics and Photonics
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• 제8권2호
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• pp.183-191
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• 2024

High-resolution retinal imaging based on adaptive optics (AO) is important for early diagnosis related to retinal diseases. However, in practical applications, closed-loop AO correction takes a relatively long time, and traditional open-loop correction methods have low accuracy in correction, leading to unsatisfactory imaging results. In this paper, a SH-U-net-based open-loop AO wavefront correction method is presented for a retinal AO imaging system. The SH-U-net builds a mathematical model of the entire AO system through data training, and the Root mean square (RMS) of the distorted wavefront is 0.08λ after correction in the simulation. Furthermore, it has been validated in experiments. The method improves the accuracy of wavefront correction and shortens the correction time.

• 대한원격탐사학회지
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• 제37권1호
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• pp.169-176
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• 2021

The Global Space-based Inter-Calibration System (GSICS) is an international partnership sponsored by World Meteorological Organization (WMO) to continue and improve climate monitoring and to ensure consistent accuracy between observation data from meteorological satellites operating around the world. The objective for GSICS is to inter-calibration from pairs of satellites observations, which includes direct comparison of collocated Geostationary Earth Orbit (GEO)-Low Earth Orbit (LEO) observations. One of the GSICS inter-calibration methods, the Ray-matching technique, is a surrogate approach that uses matched, co-angled and co-located pixels to transfer the calibration from a well calibrated satellite sensor to another sensor. In Korea, the first GEO satellite, Communication Ocean and Meteorological Satellite (COMS), is used to participate in the GSICS program. The National Meteorological Satellite Center (NMSC), which operated COMS/MI, calculated the Radiative Transfer Model (RTM)-based GSICS coefficient coefficients. The L1P reproduced through GSICS correction coefficient showed lower RMSE and Bias than L1B without GSICS correction coefficient applied. The calculation cycles of the GSICS correction coefficients for COMS/MI visible channel are provided annual and diurnal (2, 5, 10, 14-day), but long-term evaluation according to these cycles was not performed. The purpose of this paper is to perform evaluation depending on the annual/diurnal cycles of COMS/MI GSICS correction coefficients based on the ray-matching technique using Suomi-NPP/Visible Infrared Imaging Radiometer Suite (VIIRS) data as reference data. As a result of evaluation, the diurnal cycle had a higher coincidence rate with the reference data than the annual cycle, and the 14-day diurnal cycle was the most suitable for use as the GSICS correction coefficient.

• 지구물리와물리탐사
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• 제20권4호
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• pp.232-240
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• 2017

NMO보정은 탄성파 반사법 자료처리의 핵심적인 과정이고, AVO분석을 위해 가장 중요한 자료처리 단계이다. 그러나 NMO보정이 갖고 있는 근본적인 문제인 stretch 현상은 겹쌓기 단면의 품질을 저해하고 AVO분석의 신뢰성을 떨어뜨린다. 이 문제점을 해결하기 위해서 일반적으로 뮤팅을 수행하지만 stretch가 없는 NMO보정 기술을 적용한다면 먼거리 벌림 자료의 활용도가 높아진다. 이 논문에서는 먼저 NMO보정의 개념과 방법, 그리고 stretch 현상의 원인 및 특성에 대해 설명한다. Stretch 현상에 대한 직관적인 이해를 위해 단순화된 모형반응에 대한 NMO보정을 보여주고, 정량적인 이해를 위해 NMO보정에 대한 이론 식을 설명한다. Stretch를 제거하는 뮤팅에 대해 설명함으로써 기존 방법의 한계점과 새로운 해결책에 대한 필요성에 대해 논한다. Stretch가 없는 NMO보정 기법은 여러 가지 종류가 있는데 여기서는 역산 이론에 의해 이를 구현하는 방법을 사용하였다. 마지막으로 역산 기법을 통해 구현한 stretch가 없는 NMO보정을 합성자료와 현장자료에 적용하여 실제 성능을 확인해 보았다.

• 지구물리와물리탐사
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• 제5권3호
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• pp.145-149
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• 2002

정보정은 풍화층의 두께나 속도가 균질하지 않아 하부의 지층으로부터 전파된 신호의 왜곡을 보정하는 방법으로 굴절파에 근거한 정보정과 반사파에 근거한 잔여 정보정이 있다. 이 중 굴절파에 근거한 정보정은 일반적으로 분석자의 주관적인 해석에 의존하므로 많은 시간이 소요된다. 따라서 방대한 양의 자료를 처리해야하는 3차원 탄성파 탐사 자료의 정보정에 적용하는 데는 어려움이 있다. 이러한 굴절파에 근거한 정보정을 적용하기 위해서는 분석자의 해석을 최소한으로 하여 자동적으로 정보정을 수행하는 방법의 개발이 필요다. 본 연구에서는 굴절파에 근거한 정보정 방법을 육상 3차원 탄성파 탐사 자료에 대해 효과적으로 수행할 수 있는 방법에 대해 살펴보았다.

• 대기
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• 제30권4호
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• pp.319-333
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• 2020

Aircraft observations constitute one of the major sources of temperature observations which provide three-dimensional information. But it is well known that the aircraft temperature data have warm bias against sonde observation data, and therefore, the correction of aircraft temperature bias is important to improve the model performance. In this study, the algorithm of the bias correction modified from operational KMA (Korea Meteorological Administration) global model is adopted in the preprocessing of aircraft observations, and the effect of the bias correction of aircraft temperature is investigated by conducting the two experiments. The assimilation with the bias correction showed better consistency in the analysis-forecast cycle in terms of the differences between observations (radiosonde and GPSRO (Global Positioning System Radio Occultation)) and 6h forecast. This resulted in an improved forecasting skill level of the mid-level temperature and geopotential height in terms of the root-mean-square error. It was noted that the benefits of the correction of aircraft temperature bias was the upper-level temperature in the midlatitudes, and this affected various parameters (winds, geopotential height) via the model dynamics.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.471-474
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• 2004

Not all CCD pixels generate uniform value for the uniform radiance due to the different process of manufacture and each pixel characteristics. And the image data compression is essential in the real time image transmission because of the high line rate and the limited RF bandwidth. This pixel's nonuniformity and the loss compression make CCD pixel correction necessary in on-orbit condition. In the MSC system, the NUC unit, which is a part of MSC PMU, is charge of the correction for CCD each pixel. The correction is performed with the gain and the offset table for the each pixel and the each TDI mode. These correction tables are generated and programmed in the PMU Flash memory through the various image data tests at the ground test. Besides, they can be uploaded from ground station after onorbit calibration. This paper describes the principle of the table generation and the test way of the non-uniformity after NUC

• Genomics & Informatics
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• 제6권4호
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• pp.231-234
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• 2008

Precise and reliable identification of CNV is still important to fully understand the effect of CNV on genetic diversity and background of complex diseases. SNP marker has been used frequently to detect CNVs, but the analysis of SNP chip data for identifying CNV has not been well established. We compared various normalization methods for CNV analysis and suggest optimal normalization procedure for reliable CNV call. Four normal Koreans and NA10851 HapMap male samples were genotyped using Affymetrix Genome-Wide Human SNP array 5.0. We evaluated the effect of median and quantile normalization to find the optimal normalization for CNV detection based on SNP array data. We also explored the effect of Robust Multichip Average (RMA) background correction for each normalization process. In total, the following 4 combinations of normalization were tried: 1) Median normalization without RMA background correction, 2) Quantile normalization without RMA background correction, 3) Median normalization with RMA background correction, and 4) Quantile normalization with RMA background correction. CNV was called using SW-ARRAY algorithm. We applied 4 different combinations of normalization and compared the effect using intensity ratio profile, box plot, and MA plot. When we applied median and quantile normalizations without RMA background correction, both methods showed similar normalization effect and the final CNV calls were also similar in terms of number and size. In both median and quantile normalizations, RMA backgroundcorrection resulted in widening the range of intensity ratio distribution, which may suggest that RMA background correction may help to detect more CNVs compared to no correction.

• 지질공학
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• 제24권2호
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• pp.171-178
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• 2014

In seismic reflection data processing, the crossdip correction effectively focuses the stacking energy near the sharp bends of a crooked survey line. Additionally, approximate 3-D information on the reflector (e.g., true crossdip angle and lateral continuity) are locally investigated as a by-product of the crossdip correction procedure. Improvement of the signal-to-noise ratio and estimation of reflector crossdip attitude are tested, in terms of both common midpoint bin direction and processing-line type, using synthetic seismic reflection data. To effectively image the reflection energy near bends in seismic survey lines, straight-line binning is preferred to slalom-line binning.