비파괴 시험기법을 이용한 록볼트의 건전도 평가(I) -수치해석 및 실험적 적용성 평가-

이종섭,이용준,엄태원,한신인,이인모,Lee, Jong-Sub,Lee, Yong-Jun,Eom, Tae-Won,Han, Shin-In,Lee, In-Mo 한국터널지하공간학회 2006 터널기술 Vol.8 No.1

The purpose of this study is to describe the Non-Destructive Testing(NDT) of the rockbolt and investigate the applicability of the NDT methods to estimate the integrity of the rockbolt. To examine the rockbolt integrity including rockbolt itself and grouting material, two methods are adopted: numerical and experimental methods. In the numerical method, the numerical code DISPERSE is used to analyze the dispersion of the rockbolt. The dispersion curve shows the effects of the thickness and stiffness of grouted materials on the embedded rockbolt. Therefore, the optimal frequency for the integrity test of the rockbolt is obtained: 20~120kHz in L(1,0) mode. In the experimental methods, destructive and non-destructive tests are carried out in a laboratory. In the non-destructive test, the low frequency mode generated by an impact and t he high frequency mode generated by an ultrasonic transducer seem to characterize the rockbolt condition readily. The experimental results show that the guided waves attenuate more significantly when the stiffness of the grouted material increases and/or the zone of the defect increases. Meanwhile, the ultimate capacity of rockbolt was evaluated through the pull-out tests and is compared to the NDT results. This study demonstrates that the NDT is a valuable tool for the rockbolt integrity evaluation.

모바일 클라우드 환경에서 비즈니스 프로세스를 위한 XMDR-DAI를 이용한 소셜 기반의 협업 시스템

이종섭,문석재,Lee, Jong-Sub,Moon, Seok-Jae 한국정보통신학회 2015 한국정보통신학회논문지 Vol.19 No.10

In this paper, we propose a social-based collaboration systems for business process management in the mobile cloud. This XMDR-DAI is to provide services for data sharing and exchange between local systems that operate independently in a cloud environment, take charge of a social-based collaborative business process management. Social-based collaborative business processes are handled in a collision among a structure such as unit conversion, meaning conflict, and the schema mapping data resulting from the inner query. The conflict was resolved by mapping process which takes in each XMDR-DAI.

표면파에 대한 웨이블렛 변환을 이용한 모형 암반의 위상속도 예측

이종섭,엄현석,김동현,이인모,Lee, Jong-Sub,Ohm, Hyon-Sohk,Kim, Dong-Hyun,Lee, In-Mo 한국터널지하공간학회 2008 한국터널지하공간학회논문집 Vol.10 No.1

터널 막장 전방의 암반 물성 변화의 예측은 터널 시공 시 붕괴를 막을 수 있는 중요한 요소이다. 본 연구에서는 표면파에 대한 웨이블렛 변환을 이용한 모형 암반의 위상속도를 예측하는 비파괴 시험법을 제안함으로써 터널 막장 전방의 암반 물성 변화를 예측하고자 한다. 실내 실험에서는 암반을 모사하기 위하여 강도가 각각 틀린 두 층으로 이루어진 석고 모형을 사용하였다. 가진윈은 진동 발생 가능한 주파수 대역이 150 Hz에서 5 kHz인 액츄에이터를 사용하였으며, 감지기는 두 개의 가속도계가 사용되었다. 분산곡선을 계산하기 위하여 웨이블렛 변환 해석을 수행하였다. 실내 실험 결과, 근접장 효과를 없애기 위한 최소 감지기 간격이 탐측 가능 깊이의 3배 이상으로 나타났다. 정규 분포 곡선에 기초한 가중치를 이용한 간단한 역산을 제안하였고, 파장 반영계수가 0.2일 때 예측치와 실측치가 잘 일치하였다. 표면파의 전파 깊이는 파장의 $0.42{\sim}0.63$배로 나타났으며, 분산곡선에서 파장에 따라 위상속도가 변하는 구간이 역산을 통해 계산된 구간과 잘 일치하였다. 표면파에 대한 웨이블렛 변환을 이용한 위상속도의 예측은 기존의 표면파 시험법에 비해 실험 구성 및 실험 방법, 역산과정이 간단하므로 터널 막장 전방의 암반 물성 변화를 예측하는데 효율적인 적용이 가능할 것으로 판단된다. Prediction of ground condition ahead of tunnel face might be the most important factor to prevent collapse during tunnel excavation. In this study, a non-destructive method to evaluate the phase velocity in model rock mass using wavelet transform of surface wave was proposed aiming at ground condition assessment ahead of tunnel face. Model tests using gypsum as a rocklike material composed of two layers were performed. A Piezoelectric actuator with frequencies ranging from 150 Hz to 5 kHz was selected as a harmonic source. The acceleration history was measured with two accelerometers. Wavelet transform analysis was used to obtain the dispersion curves from the measured data. The experimental results showed that the near-field effects can be neglected if the distance between two receivers is chosen to be three times the wavelength. A simple inversion method using weighted factor based on the normal distribution was proposed. The inversion results showed that the predicted phase velocity agreed reasonably well with the measured one when the wavelength influence factor was 0.2. The depth of propagation of surface wave was from 0.42 to 0.63 times the wavelength. The range of wavelength varying with phase velocity in dispersion curve matched well with that estimated by inversion technique.

현장타설말뚝의 네킹 결함 평가를 위한 전자기파의 적용성 연구

이종섭,송정욱,유정동,Lee, Jong-Sub,Song, Jung Wook,Yu, Jung-Doung 한국지반공학회 2018 한국지반공학회논문집 Vol.34 No.4

The objective of this study is to demonstrate the suitability of electromagnetic waves for evaluating necking defects in bored piles using electromagnetic waves. Experiments are conducted with small-scaled defective model pile with diameter of 150 mm and length of 270 mm. Two necking defects are generated at the upper and lower positions on two different sides of the model pile, respectively. The other two necking defects are generated at the upper and lower positions on the same side of the model pile. Electrical wires are installed alongside the stainless steel wire of a steel cage to configure a two-conductor transmission line. A time-domain reflectometer is used to generate and defect electromagnetic waves. The experimental results show that electromagnetic waves are reflected at the necking defects and the end of the model pile. In addition, calculated defect locations are almost the same as actual defect locations. This study demonstrates that electromagnetic waves can be effective tool for evaluating necking defects in bored piles.

광유의 절연파괴에 미치는 전극간격 및 침전극 곡률반경의 영향

이종섭,신태수,이운용,박영국,강성화,임기조 ( Jong Sub Lee,Tae Su Shin,Un Yong Lee,Young Kuk Park,Seong Hwa Kang,Kee Joe Lim ) 한국전기전자재료학회 1997 한국전기전자재료학회 추계학술대회논문집 Vol.1997 No.1

보행자의 상황을 추론하는 플랫폼에 관한 연구

이종섭(Jong-Sub Lee) 융복합지식학회 2019 융복합지식학회논문지 Vol.7 No.1

본 논문은 교통환경 안정성을 확보할 수 있도록 보행자의 상황을 추론하는 플랫폼을 제안한다. 본 제안 플랫폼은 보행자들의 급작스러운 보행 상황 변화를 실시간으로 분석하여 보행중에 낙상상태를 판단하는 플랫폼이다. 기존에 연구된 낙상 상태 기술들은 다수가 상황이 변했다는 행위 만을 판단하여 서비스를 제공하였다. 그러나 보행중에 발생하는 낙상은 발생 여부 자체만이 아니라 낙상이 일어나기 전과 후의 상황 또는 낙상이 발생한 위치를 인지하는 것이 중요하다. 본 논문에서는 스마트폰의 가속도 센서를 이용해 보행중에 낙상 상황여부와 낙상 발생 전과 후의 상황을 인지하도록 한다. 이에, 본 논문에서는 Dual Logic 보행행동상황 인식 알고리즘과 보행정보 및 위치정보를 중심으로 분석하고, 보행 낙상 판단을 모델링하는 기술을 접목하여 플랫폼을 제안한다. This paper proposes a platform for inferring the pedestrian situation in order to secure the stability of the traffic environment. The proposed platform is a platform to analyze the sudden change of the walking situation of the pedestrians in real time and to determine the fall status during walking. Many of the existing fallen state techniques have provided services by judging only the fact that the situation has changed. However, it is important to recognize not only the occurrence of falls during walking, but also the situation before and after the fall or where the fall occurred. In this paper, we use accelerometer of smartphone to recognize whether or not a fall occurs while walking and before and after a fall. In this paper, we propose a platform based on Dual Logic gait recognition algorithm, gait and position information analysis, and technology for modeling gait fall determination.

실내식물 및 색채자극이 대뇌 활성도 및 감정반응에 미치는 영향

이종섭(Lee Jong-Sub),손기철(Son Ki-Cheol) 한국원예학회 1999 Horticulture, Environment, and Biotechnology Vol.40 No.6

니켈 급성독성에 대한 인삼 사포닌의 방어효과 연구

이종섭 ( Jong Sub Lee ) 대한보건협회 1992 대한보건연구 Vol.18 No.2

기술보고 : Field Velocity Probe를 활용한 연약지반 압밀 평가

이종섭 ( Jong Sub Lee ),김영석 ( Young Seok Kim ),홍승서 ( Seung Seo Hong ),윤형구 ( Hyung Koo Yoon ) 대한지질공학회 2013 지질공학 Vol.23 No.4

The Field Velocity Probe (FVP) has been widely applied to determine the various characteristics of soils. This study seeks to estimate soil consolidation characteristics using an FVP and to increase its application in the field. The specimens were extracted from depths of 3 and 6 m at the study site, an area of soft clay in Incheon. In laboratory testing, the specimens were placed in an improved oedometer cell to measure shear wave velocity, and statistical analysis was performed to compare the results of effective stress and shear wave velocity. FVP enables increased resolution in the field because it measures the shear wave velocity every 20 cm. To estimate the condition of consolidation, we compared the results of shear wave velocities between those obtained in the laboratory and those in the field. The field conditions are used to analyze overconsolidated and normally consolidated soils at depths of 3 and 6 m, respectively. The results show that FVP is a suitable method for estimating the degree of consolidation.

빅데이터 분석을 이용한 포스트 COVID 시대의 여행 스트레스 연관 키워드 분석에 관한 연구

이종섭(Jong-Sub Lee),문석재(Seok-Jae Moon) 융복합지식학회 2021 융복합지식학회논문지 Vol.9 No.4

2019년 12월 시작된 신종 감염병 COVID-19는 전 세계를 팬데믹 시대로 몰아넣었다. 그에 따라서 세계 각국은 COVID-19 확산을 우려하여 내외국인 입국제한 조치를 취하였고, 이로 인하여 관광객들의 이동이 감소하면서 관광산업은 위기 상황에 직면하였다. 이로 인하여 여행의 제한이 생기면서 ‘COVID-블루’ 같은 키워드가 급증했으며 우울의 빈도가 높아졌다. 기존에는 COVID-19와 스트레스의 관계는 직무에 관한 내용이었으며, 여행의 관계 역시 대책 방안이 아닌 분석 자료에 대한 내용이다. 본 논문은 COVID-19시대의 스트레스 의미 네트워크를 분석하여 키워드를 도출하고 포스트 COVID-19 시대의 여행 관련 새로운 방향을 제시하는데 기여하고자 하는 연구이다. 본 논문은 COVID-19로 인한 스트레스를 빅데이터 분석 툴인 텍스톰을 활용하여 분석을 진행하였고, UCINET6를 이용해 의미연결망 분석을 실시하였다. 또한, 유사점을 가진 단어들의 군집 도출을 위해 CONCOR 분석을 실시하여 키워드를 분류하였다. 그리고 TextRank를 이용하여 키워드 분석을 하였다. 하지만 COVID-19 시작부터 현재까지 여행, 스트레스 위주의 자료를 수집했기 때문에 분석 자료의 수를 더 늘려 추후 더 많은 자료의 분석이 필요하다. The novel infectious disease COVID-19, which started in December 2019, has plunged the world into a pandemic era. As a result, countries around the world took measures to restrict entry for domestic and foreign nationals due to concerns about the spread of COVID-19. As travel restrictions were imposed due to COVID-19, keywords such as ‘corona blue’ surged, and the frequency of depression increased. Previously, the relationship between Corona 19 and stress was about work, and the relationship between Corona 19 and travel is also about analysis data, not about countermeasures. Therefore, this paper is a study that aims to contribute to deriving keywords by analyzing the stress semantic network in the era of COVID-19 and suggesting a new direction related to travel in the post-COVID-19 era. In this paper, stress caused by Corona 19 was analyzed using Textome, a big data analysis tool, and semantic network analysis was performed using UCINET6. In addition, keywords were classified by performing CONCOR analysis to derive clusters of words with similarities. And keyword analysis was performed using TextRank. However, since we have collected travel and stress-focused data from the beginning of COVID-19 to the present, it is necessary to analyze more data in the future by increasing the number of analyzed data.