• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.984-996
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• 2009

When evaluating the general subgrade states such as geology, stiffness, underground water, compaction and deformation in the Gyeongbu high speed railway, some applicable testing methods should be selected because lots of trains are currently running. The applicable methods includes not only non-destructive tests such as GPR test, electricity resistivity test, MASW proving, but also standard penetration test (SPT), core test, elastic wave tomography through drilling boreholes and measurements using settlement measuring system or inclinometer, etc. In order for evaluating the subgrade states in the Gyeongbu high speed ralway, this study performed GPR test in several sections and drilling boreholes whose locations were chosen after comparing GPR test results and track maintenance history. Furthermore, the progress of subgrade deformations was analysed by comparing previous and this time GPR test results. The results of this study shall be used to understand the general states of currently operating Gyeongbu high speed railway.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표대회 논문집(III)
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• pp.761-766
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• 1998

GPR(Ground Penetrating Radar) designed with a digital-based signal processing technology utilizes to identify very easily the location, the thickness and the level of either an underground embedment or an underground structure. Prior to use of this GPR equipment on pavement of about 15cm thick, the equipment should foremost be calibrated on a known sample under known condition. The purpose of this study is to verify the applicability of the GPR equipment to a model pavement of about 15cm thick. As part of this effort, the general approach of this study is to verify the applicability of the GPR equipment by various thickness levels and its error ranges thru a statistical analysis.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2004년도 정기총회 및 제6최 특별 심포지움
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• pp.49-69
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• 2004

문화재 발굴에 있어서 물리탐사의 중요한 역할중의 하나는 효율적이고도 체계적인 발굴을 위하여 지하 천부에 대한 정보를 제공함에 있다고 할 수 있다. 지표 레이다 탐사(GPR)는 지하 천부의 고분해능 영상을 제공하여 줄 수 있기 때문에 고고학 탐사에 있어서 중요한 물리탐사 방법 중의 하나로 인식된다. 역사유물은 지질구조와는 달리 일정한 방향성이 없이 매몰되어 있는 경우가 많으므로 근본적으로 2차원 탐사보다는 3차원 탐사가, 그리고 측선탐사보다는 면적탐사의 개념을 동원하여 탐사함이 바람직하다. 그러나 3차원 GPR 탐사는 매우 조밀하게 측선을 설정하고 대단히 많은 자료를 획득하여야 가능하므로 넓은 지역의 조사에 항상 적용하기란 현실적으로 매우 어렵다. 이와 같은 문제점을 극복하기 위해서는 효율적인 탐사방법을 고안함이 매우 중요하다. 이 연구에선 부여 가탑리 지역의 백제시대 유적지 발굴조사에 선행하여 3차원 GPR 탐사를 중심으로 한 물리탐사를 수행하였다. 조사의 1차적인 목적은 지하 하부 구조에 대한 고분해능 영상을 제공함으로써 계획된 유적발굴에 도움을 주고자 함에 있었다. 한편 고고학 발굴을 위한 효율적인 지하 영상화 방법을 제공하기 위하여, 다중 채널 안테나와 자동 측량 시스템을 채용한 GPR 자동연속탐사 시스템의 유적지발굴에 대한 효용성을 검증함에 그 부차적인 목적이 있었다. 자료측정의 효율성을 제고하기 위하여 미리 측선을 설정하지 않고 조사영역 내에서 임의의 방향으로 자료를 취득하는 개념을 채택하였다. 이와 같은 시스템을 이용하여 탐사한 결과, 2일 간에 걸친 현장 탐사 결과로써 약 $17,000 m^2$에 걸친 지역에 대한 3차원 탐사자료를 얻을 수 있었다. 또한 미리 측선을 설정하지 않고 자료를 획득하였음에도 불구하고, 전산처리 결과 획득한 지하 영상으로부터 경작지, 수로, 인공 구조물 또는 유물 등의 존재를 알려주는 이상대들을 정밀하게 파악할 수 있었다. 이 연구 사례를 통하여 3차원 GPR 탐사 또한 국부적인 이상대의 규명뿐만 아니라 광역적인 고고학 조사에도 다른 물리탐사와 마찬가지로 쉽게 활용될 수 있다는 결론을 얻을 수 있었다. 3차원 GPR 탐사가 향후 국내의 문화재 조사에 표준화된 탐사과정 중의 하나로써 적극 활용되길 기대한다.

• 한국도로학회논문집
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• 제18권6호
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• pp.61-67
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• 2016

OBJECTIVES : The objective of this study is to detect road cavities using multi-channel 3D ground penetrating radar (GPR) tests owned by the Seoul Metropolitan Government. METHODS : Ground-penetrating radar tests were conducted on 204 road-cavity test sections, and the GPR signal patterns were analyzed to classify signal shape, amplitude, and phase change. RESULTS : The shapes of the GPR signals of road-cavity sections were circular or ellipsoidal in the plane image of the 3D GPR results. However, in the longitudinal or transverse direction, the signals showed mostly unsymmetrical (or symmetrical in some cases) parabolic shapes. The amplitude of the GPR signals reflected from road cavities was stronger than that from other media. No particular pattern of the amplitude was found because of nonuniform medium and utilities nearby. In many cases where road cavities extended to the bottom of the asphalt concrete layer, the signal phase was reversed. However, no reversed signal was found in subbase, subgrade, or deeper locations. CONCLUSIONS : For detecting road cavities, the results of the GPR signal-pattern analysis can be applied. In general, GPR signals on road cavity-sections had unsymmetrical hyperbolic shape, relatively stronger amplitude, and reversed phase. Owing to the uncertainties of underground materials, utilities, and road cavities, GPR signal interpretation was difficult. To perform quantitative analysis for road cavity detection, additional GPR tests and signal pattern analysis need to be conducted.

• Molecules and Cells
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• 제43권4호
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• pp.340-349
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• 2020

Oleoylethanolamide (OEA), a bioactive lipid in bone, is known as an endogenous ligand for G protein-coupled receptor 119 (GPR119). Here, we explored the effects of OEA on osteoclast differentiation, function, and survival. While OEA inhibits osteoclast resorptive function by disrupting actin cytoskeleton, it does not affect receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation. OEA attenuates osteoclast spreading, blocks actin ring formation, and eventually impairs bone resorption. Mechanistically, OEA inhibits Rac activation in response to macrophage colony-stimulating factor (M-CSF), but not RANKL. Furthermore, the OEA-mediated cytoskeletal disorganization is abrogated by GPR119 knockdown using small hairpin RNA (shRNA), indicating that GPR119 is pivotal for osteoclast cytoskeletal organization. In addition, OEA induces apoptosis in both control and GPR119 shRNA-transduced osteoclasts, suggesting that GPR119 is not required for osteoclast apoptosis. Collectively, our findings reveal that OEA has inhibitory effects on osteoclast function and survival of mature osteoclasts via GPR119-dependent and GPR119-independent pathways, respectively.

• 한국지반공학회논문집
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• 제37권9호
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• pp.13-24
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• 2021

최근 자갈도상궤도의 유지관리 시 지반투과레이더(GPR) 장비를 이용한 지반 내부의 파울링 양상을 검측하는 시도가 이루어지고 있다. 하지만, 복잡한 지반조건이 혼재된 현장에서 다량의 노이즈가 포함된 채로 얻어지는 GPR 신호 자료 판독은 전문가의 경험에 의존하는 경우가 많으며, 정밀한 분석에 어려움도 많다. 따라서, 본 연구에서는 python 기반의 오픈소스코드인 gprMax와 RSA(Random sequential Absorption) 알고리즘을 이용하여 자갈도상 재료의 파울링 정도에 따른 GPR 신호특성을 정량적으로 분석하고 평가할 수 있는 수치해석 기법을 제안하였다. 해석모델의 예측 정확도를 평가하고자 모형시험체를 제작하여 시험 결과와 해석결과를 서로 비교하여 해석모델의 예측 정밀도를 확인하였다. 또한, 다양한 시험조건 별 모형체 시험 및 해석에서의 파울링층의 식별 여부를 평가하였으며 그 결과를 분석하였다.

• Biomolecules & Therapeutics
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• 제30권1호
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• pp.48-54
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• 2022

GPR43 (also known as FFAR2), a metabolite-sensing G-protein-coupled receptor stimulated by short-chain fatty acid (SCFA) ligands is involved in innate immunity and metabolism. GPR43 couples with Gα_i/o and Gα_q/11 heterotrimeric proteins and is capable of decreasing cyclic AMP and inducing Ca²⁺ flux. The GPR43 receptor has additionally been shown to bind β-arrestin 2 and inhibit inflammatory pathways, such as NF-κB. However, GPR43 shares the same ligands as GPR41, including acetate, propionate, and butyrate, and determination of its precise functions in association with endogenous ligands, such as SCFAs alone, therefore remains a considerable challenge. In this study, we generated novel synthetic agonists that display allosteric modulatory effects on GPR43 and downregulate NF-κB activity. In particular, the potency of compound 187 was significantly superior to that of pre-existing compounds in vitro. However, in the colitis model in vivo, compound 110 induced more potent attenuation of inflammation. These novel allosteric agonists of GPR43 clearly display anti-inflammatory potential, supporting their clinical utility as therapeutic drugs.

• 지구물리와물리탐사
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• 제7권4호
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• pp.256-261
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• 2004

경주의 월성에 대한 발굴 작업 없이도 고고학적인 호기심을 충족시킬 수 있도록 비파괴 조사방법의 일환인 GPR(Ground Penetrating Radar) 탐사법을 적용하여 지하유구의 존재 상황을 조사하였다. 이는 현대고고학과 지구물리학을 접목하여 향후 발굴계획이나 고고학적 연구에 과학적이고 체계적인 접근 전기를 마련하고자 하는 의미도 있다. GPR 탐사는 석빙고 앞 및 성의 동편 끝 지역에서 실시되었으며 향후 3차원 자료처리 및 해석을 위해 조사대상지 전체에 대해 조밀한 측선을 설정하였다. 구성된 3차원 볼륨 자료를 고고학적으로 해석한 결과, 대형 건물지 7채와 담장 및 성의 출입시설, 수많은 초석들, 도로,그리고 원지 등을 추정할 수 있었다.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2008년도 공동학술대회
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• pp.113-118
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• 2008

Among the geophysical methods, Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT) comprise the most promising techniques in resolving buried archaeological structures in urban territories. In this work, two case studies which involve an integrated geophysical survey employing the surface three dimensional (3D) ERT and GPR techniques, in order to archaeologically characterize the investigated areas, are presented. Totally more than 4000 square meters were investigated from the test field sites, which are located at the centre of two of the most populated cities of the island of Crete, in Greece. The ERT and the GPR data were collected along dense and parallel profiles. The subsurface resistivity structure was reconstructed by processing the apparent resistivity data with a 3D inversion algorithm. The GPR sections were processed with a systematic way applying specific filters to the data in order to enhance their information context. Finally, horizontal depth slices representing the 3D variation of the physical properties were created and the geophysical anomalies were interpreted in terms of possible archaeological structures. The subsequent excavations in one of the sites verified the geophysical results, enhancing the applicability of ERT and GPR techniques in the archaeological exploration of urban territories.

• Geomechanics and Engineering
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• 제33권2호
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• pp.203-209
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• 2023

One major advantage of ground penetrating radar (GPR) over other field test methods is its ability to obtain subsurface images of roads in an efficient and non-intrusive manner. Not only can the strata of pavement structure be retrieved from the GPR scan images, but also various irregularities, such as cracks and internal cavities. This article introduces a deep learning-based approach, focusing on detecting subsurface cracks by recognizing their distinctive hyperbolic signatures in the GPR scan images. Given the limited road sections that contain target features, two data augmentation methods, i.e., feature insertion and generation, are implemented, resulting in 9,174 GPR scan images. One of the most popular real-time object detection models, You Only Learn One Representation (YOLOR), is trained for detecting the target features for two types of subsurface cracks: bottom cracks and full cracks from the GPR scan images. The former represents partial cracks initiated from the bottom of the asphalt layer or base layers, while the latter includes extended cracks that penetrate these layers. Our experiments show the test average precisions of 0.769, 0.803 and 0.735 for all cracks, bottom cracks, and full cracks, respectively. This demonstrates the practicality of deep learning-based methods in detecting subsurface cracks from GPR scan images.