• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.628-633
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• 2018

The accuracy of GNSS depends on several factors from the equipment used in data processing because GNSS positioning can be used differently depending on the accuracy required. In the case of the control point surveying requiring high accuracy, GNSS surveying is performed using the relative positioning method, and the observation time and data processing s/w are used differently depending on the class of the control points. On the other hand, the accuracy of academic software depends on the skill of the user, so it may be better to use commercial software in the case of a short baseline. In this study, the results of GNSS survey data were compared using scientific software and commercial software. The results showed that the horizontal position showed a difference of less than 2 cm and the height showed a difference of less than 5 cm. These differences were found to be in the error ranges specified in the unified control point survey regulations. Based on the above results, the commercial s/w can be used for GNSS data processing at the midterm baseline rather than the long baseline.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.53-53
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• 2019

방울다다기양배추는 아직까지 국내에서는 소비자들에게 인지도가 낮은 작물이지만 최근 식생활 및 소비 패턴이 변화하면서 편의성, 차별성 등이 중요시면서 미니 과일, 미니채소류에 대한 관심이 증가하고 있다. 또한 외국의 도입 채소류에 대한 관심이 증가하면서 2013년 방울다다기양배추 수입량이 36톤이었던 것이 2015년에는 14.3배가 증가한 515톤으로 증가하였다. 이를 통해 방울다다기양배추가 가지고 있는 기능성과 미니채소에 대한 관심으로 지속적으로 소비가 증가할것으로 예상되고 있다. 이와같이 증가추세에 있는 방울다다기양배추의 수입을 대체하기 위해서는 국내 재배면적 확대가 필요하나 저온성 작물인 방울다다기양배추는 고온기 남부지역에서는 재배가 어려워 제주지역의 겨울재배 작형으로 제한되어 재배가 되고 있다. 따라서 제주지역의 겨울재배 작형과 연계하여 강원도 고랭지의 서늘한 여름 기후를 이용하여 단경기인 9~11월에 생산할 수 있는 여름재배 작형을 개발할 필요성이 있어 시험을 수행하였다. 본 시험은 2018년~2019년 태백 철암의 노지(표고 750 m)에서 시험품종은 "브릴리언트"를 이용하여 3월 하순 파종하여 50일 육묘하여 5월 10일 포장에 정식하였다. 흑색멀칭한 시험포장에 $80{\times}30cm$부터 $80{\times}60cm$까지 10 cm 간격으로 차이를 두고 정식하였으며 정식 전 N-P-K = 20-15-20 kg/10 a를 시비하였고 시험포장은 수확까지 병해충 방제 등 주기적으로 관리하면서 생육특성 및 수량성을 조사하였다. 재식거리별 생육상황을 비교한 결과 초장은 처리간 큰 차이가 없었고 경경은 재식거리가 커질수록 증가하는 경향이었다. 또한 엽장 및 엽폭은 처리간의 경향이 없었으며 엽수는 재식거리가 커질수록 증가하였고 $80{\times}30cm$ 처리시 80매내외였던 것이 $80{\times}50cm$ 이상일 경우 100매 이상으로 증가하였다. 재식거리별 구의 특성을 조사한 결과 구경은 처리간 큰 차이는 없었으나 재식거리가 커질수록 구경이 다소 증가하였으며 구중도 증가하는 경향이었다. 방울다다기양배추의 구의 엽수는 처리간 큰 차이가 없었고 경도 및 당도도 큰 차이가 없었다. 처리별 수량은 $80{\times}40cm$와 $80{\times}50cm$ 처리에서 수량이 다소 증가하였고 상품화율은 $80{\times}50{\sim}60cm$ 처리에서 80%이상으로 높았다. 따라서 방울다다기양배추의 여름 고랭지 재배시 재식거리는 $80{\times}50cm$ 처리시 생육 및 엽수 증가에 따른 구의 형성이 증가하여 수량성이 높아지고 상품화율도 증가하였다.

• Korean Journal of Remote Sensing
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• v.23 no.6
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• pp.559-566
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• 2007

The generation of precise digital elevation model (DEM) is very important in coastal area where time series are especially required. Although a LIDAR system is useful in coastal regions, it is not yet popular in Korea mainly because of its high surveying cost and national security reasons. Recently, precise DEM has been made using radar interferometry and waterline methods. One of these methods, spaceborne imaging radar interferometry has been widely used to measure the topography and deformation of the Earth. We acquired ALOS PALSAR FBD mode (Fine Beam Dual) data for evaluating the quality of interferograms and their coherency. We attempted to construct DEM using ALOS PALSAR pairs - One pair is 2007/05/22 and 2007/08/22, another pair is 2007/08/22 and 2007/10/22 with respective perpendicular baseline of 820 m, 312m and respective height sensitivity of 75 m and 185m at southern of Ganghwa tidal flat, Siwha- and Hwaong-lake over west coastal of Korea peninsula. Ganghwa tidal flat has low coherence between 0.3 and 0.5 of 2007/05/22 and 2007/08/22 pair. However, Siwha-lake and Hwaong-lake areas have a higher coherence value (From 0.7 and 0.9) than Ganghwa tidal area. The reason of difference coherence value is tidal condition between tidal flat area (Ganghwa) and reclaimed zone (Siwha-lake and Hwaong-lake). Therefore, DEM was constructed by ALOS PALSAR pair over Siwha-lake and Hwaong-lake. If the temporal baseline is enough short to maintain the coherent phases and height sensitivity is enough small, we will be able to successfully construct a precise DEM over coastal area. From now on, more ALOS PALSAR data will be needed to construct precise DEM of West Coast of Korea peninsular.

• Journal of the Korean earth science society
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• v.34 no.7
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• pp.626-632
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• 2013

In this study the GPS Precipitable Water Vapor (PWV) was derived and evaluated by a radiosode measure during the winter intensive observation in Gangneung site from January 5 till February 29 in 2012. Bernise 5.0 software was used to derive the GPS data. GPS-derived PWV from Zero difference (GANG) and Single difference (GANG and DAEJ) was high variance in time and about 5 times the PWV of radiosonde. GPS post-processing has been performed from two additional IGS site (Xian Dao, Ibaraki-ken) in order to correct the absolute troposphere errors. As a result, the mean bias error (MBE) and root mean square error (RMSE) and correlation compared with radiosonde measure were 0.67 mm, 6.40 mm, and 0.93, respectively. In order to correct the relative troposphere errors from the altitudinal difference between the two GPS receivers, we calculated the GPS-derived PWV by adding the data of GPS that was installed in Gangneung-Wonju University near the Gangwon Regional Meteorological Administration. In the end, the improved result showed that MBE, RMSE and correlation in comparison with radiosonde measures were 0.61 mm, 5.79 mm, and 0.93, respectively.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.16 no.1
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• pp.27-40
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• 1998

This paper addresses the suitability of GPS positioning technology to monitoring deformation and movement of structures. The first part of the study is an empirical quantitative study of the repeatability of GPS observations and the second part is a performance evaluation of kinematic GPS, which requires only a few minutes per a point, for monitoring deformation of an engineering structure. On the test network for monitoring of a earth am, four observations have been conducted repeatedly on different seasons and water levels. The reference network was observed in static mode, and monitoring points were observed respectively in rapid-static mode as well as in kinematic mode in each epoch and then the results were compared with those obtained by conventional surveying techniques. The repeatability of baseline vectors to better than average 7 mm in three dimensions was achieved in base line observations between reference points and also the unclosure of reference networks showed the range of 4 ppm to 27 ppm. Compared with conventional surveying techniques, the kinematic approach showed the differences of 3∼4 m in slope distances which were observed from reference points to monitoring points, and showed the differences of 4∼8 m in height. It was ascertained that the kinematic GPS technology provides an efficient alternative to deformation monitoring by conventional means which are capable of detecting movements in the order of 5 mm.

• Korean Journal of Remote Sensing
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• v.29 no.1
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• pp.21-34
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• 2013

Permanent Scatterer InSAR (PSInSAR) technique extracts permanent scatterers exhibiting high phase stability over the entire observation period and calculates precise time-series deformation at Permanent Scatterer (PS) points by using single master interferograms. This technique is not a good method to apply on nature environment such as forest area where permanent scatterers cannot be identified. Another muti-temporal Interferometric Synthetic Aperture Radar (InSAR), Small BAseline Subset (SBAS) technique using multi master interferograms with short baselines, can be effective to detect deformation in forest area. However, because of the error induced from phase unwrapping, the technique sometimes fails to estimate correct deformation from a stack of interferograms. To overcome those problems, we introduced new multi-temporal InSAR technique, called Temporarily Coherence Point InSAR (TCPInSAR), in this paper. This technique utilizes multi master interferograms with short baseline and without phase unwrapping. To compare with traditional multi-temporal InSAR techniques, we retrieved spatially changing deformation because PSs have been found enough in forest area with TCPInSAR technique and time-series deformation without phase unwrapping error. For this study, we acquired ERS-1 and ERS-2 SAR dataset on Augustine volcano, Alaska and detected deformation in study area for the period 1992-2005 with SBAS and TCPInSAR techniques.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.4
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• pp.431-439
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• 2010

Cross-interferometic synthetic aperture radar (CInSAR) technique from ERS-2 and Envisat images is capable of generating submeter-accuracy digital elevation model (DEM). However, it is very difficult to produce high-quality CInSAR-derived DEM due to the difference in the azimuth and range pixel size between ERS-2 and Envisat images as well as the small height ambiguity of CInSAR interferogram. In this study, we have proposed an efficient method to overcome the problems, produced a high-quality DEM over northern Alaska, and compared the CInSAR-derived DEM with the national elevation dataset (NED) DEM from U.S. Geological Survey. In the proposed method, azimuth common band filtering is applied in the radar raw data processing to mitigate the mis-registation due to the difference in the azimuth and range pixel size, and differential SAR interferogram (DInSAR) is used for reducing the unwrapping error occurred by the high fringe rate of CInSAR interferogram. Using the CInSAR DEM, we have identified and corrected man-made artifacts in the NED DEM. The wave number analysis further confirms that the CInSAR DEM has valid Signal in the high frequency of more than 0.08 radians/m (about 40m) while the NED DEM does not. Our results indicate that the CInSAR DEM is superior to the NED DEM in terms of both height precision and ground resolution.

• Journal of Broadcast Engineering
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• v.19 no.5
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• pp.677-686
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• 2014

This paper analyzes the 3D accuracy of stereo images captured from a mobile phone. For 3D accuracy evaluation, we have compared the accuracy result according to the amount of the convergence angle. In order to calculate the 3D model space coordinate of control points, we perform inner orientation, distortion correction and image geometry estimation. And the quantitative 3D accuracy was evaluated by transforming the 3D model space coordinate into the 3D object space coordinate. The result showed that relatively precise 3D information is generated in more than $17^{\circ}$ convergence angle. Consequently, it is necessary to set up stereo model structure consisting adequate convergence angle as an measurement distance and a baseline distance for accurate 3D information generation. It is expected that the result would be used to stereoscopic 3D contents and 3D reconstruction from images captured by a mobile phone camera.

• Korean Journal of Cognitive Science
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• v.14 no.1
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• pp.29-40
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• 2003

Cross-Language Information Retrieval (CLIR) deals with the documents in various languages by one language query. A user who uses one language can retrieve the documents in another language through CLIR system. In CLIR, query translation method is known to be more efficient. For the better performance of query translation, we need more resources like dictionary, ontology, and parallel/comparable corpus but usually not available. This paper proposes a new concept called the Common Base Axis which is adapted to Korean-English Query translation ann a new weighting method in dictionary based query translation. The essential idea is that we can express Korean and English word in one vector space by Common Base Axis and use it in calculating sense distance for query weighting. The experiments show that Common Base Axis gives us good performance without ontology and is especially good for one word query translation.

• Aerospace Engineering and Technology
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• v.8 no.1
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• pp.132-137
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• 2009

This study has regard to classification by using multi-temporal SAR data. Multi-temporal JERS-1 SAR images are used for extract the land cover information and possibility. So far, land cover information extracted by high resolution aerial photo, satellite images, and field survey. This study developed on multi-temporal land cover status monitoring and coherence information mapping can be processing by L band SAR image. From July, 1997 to October, 1998 JERS SAR images (9 scenes) coherence values are analyzed and then extracted land cover information factors, so on. This technique which forms the basis of what is called SAR Interferometry or InSAR for short has also been employed in spaceborne systems. In such systems the separation of the antennas, called the baseline is obtained by utilizing a single antenna in a repeat pass.