Artificial intelligence (AI) has been applied to most industries by enhancing automation and contributing greatly to efficient processes and high-quality production. This research analyzes the applications of AI-based automobile accident prevention systems. It deals with AI-based collision prevention systems that learn information from various sensors attached to cars and AI-based accident detection systems that automatically report accidents to the control center in the event of a collision. Based on the literature review, technological and institutional changes are taking place at the national levels, which recognize the effectiveness of the systems. In addition, start-ups at home and abroad as well as major car manufacturers are in the process of commercializing auto parts equipped with AI-based collision prevention technology.

목 적 : 대퇴골두 충돌 증후군의 진단과 치료을 위하여 자기공명 3D 재구성 영상과 컴퓨터 단층 촬영 3D 재구성 영상을 비교 평가하여 유용성을 알아보고자 하였다. 대상 및 방법 : 2014년 6월부터 12월까지 본원에서 Hip 자기공명 영상 검사(MRI)와 3D Hip 컴퓨터 단층 촬영(CT)을 동시 시행한 환자 31명 (남: 21명 평균연령: 35세 여: 10명 평균연령: 40.3세)을 대상으로 분석하였다. MR System은 3.0T Magnetom Tim Verio (Siemens Healthcare, Germany)를 사용하여 3D T2 trufi sequence을 시행하였다. 3D T2 trufi의 영상변수는 TR은 5.64msec 이고 TE는 2.48msec 이며, NEX는 1, Slice thickness는 4mm, Matrix: 165×256, FOV: 230×230 이며, Scan time은 2분45초가 소요 되었다. 컴퓨터 단층 촬영의 Protocol은 관전압 120 kVp, 관전류 150 mAs, pitch 1 mm, Increment 0.7 mm, Kernel값은 B60S Sharp을 사용하였다. 영상평가는 정형외과 전문의 1명과 영상의학과 전문의 1명이 MR과 CT modality에서 Hip joint articular transverse ligament의 6 o’clock을 중심으로 superior을 12 o’clock, Labrum의 전면을 3 o’clock, 반대쪽을 9 o’clock로 기술하는 clock face을 재구성 한 후 11 o’clock에서 A.retinacular vessel, B. head neck junction, 12 o’clock A. Epiphyseal line, B. Cam lesion, 1,2,3,4 o’clock의 Cam lesion, Posterior Cam lesion확인 여부를 리커트(Likert scale) 5점 척도로 평가하였다(Independent t-test p<0.05). 평가자간 신뢰도 검증은 Cohen’s weighted Kappa 검증을 이용하여 일치성 검증을 하였다. 결 과 : 영상의 정성적 평가를 위한 리커드 척도 결과 11 o’clock A. retinacular vessel MR 평균 값 3.69±1.0, CT 평균값 2.8±0.78이며 통계적으로 유의하였다(p<0.001). B. head neck junction은 두 평가자간 차이가 없었다(p<0.416). 12 o’clock A. Epiphyseal line MR 평균값 3.54±1.00, CT 평균값 4.5±0.62이었다(p<0.000). B. Cam lesion은 두 평가자간 차이가 없었다(p<0.532). 1,2,3,4 o’clock 의 Cam lesion과 Posterior Cam lesion은 통계적으로 유의하지 않았다(p<0.656, p<0.658). weighted Kappa 검증 결과 11 o’ clock A.retinacular vessel CT K값이 0.663으로 가장 낮은 일치도였으며, 각각의 평가 항목의 일치도 평가결과 매우 높은 결과로 두 평가자간 높은 신뢰도를 보여주었다. 결 론 : 대퇴골두 충돌 증후군의 진단과 관절경을 적용하기 위하여 시행하는 CT 3D-Hip 검사는 MRI 3D clock face 재구성 기법으로 대체 가능하며, 이로 인해 불필요한 환자의 피폭선량을 최소화 할 수 있다. 또한 Cam lesion에 대한 표준화된 영상을 제시함으로써 고관절 수술 시 의료진에게 신뢰할 수 있는 영상을 제공하여 수술 전 효과적인 계획을 수립할 수 있을 것으로 사료된다.

목 적 : Hip FAI 진단과 수술 계획 시 이루어지는 CT 촬영을 최소화하고 Hip FAI MRI 검사시 3D 영상을 추가로 활용하여 CT 영상으로 이루어지는 Hip Clock face 영상을 MRI 3D영상으로 대체할 수 있는지 비교 평가하였다. 대상 및 방법 : 2014년 6월부터 12월까지 본원에서 Hip 자기공명 영상 검사(MRI)와 3D Hip 컴퓨터 단층 촬영(CT)을 동시 시행한 환자 31명 (남: 21명 평균연령: 35세 여: 10명 평균연령: 40.3세)을 대상으로 분석하였다. MR System은 3.0T Magnetom Tim Verio (Siemens Healthcare, Germany)를 사용하여 3D T2 trufi sequence를ㄹ 시행하였다. 3D T2 trufi의 영상변수는 TR은 5.64msec 이고 TE는 2.48msec 이며, NEX는 1, Slice thickness는 1mm, Matrix: 165×256, FOV: 230mm×230mm이며, Scan time은 2분45초가 소요 되었다. 컴퓨터 단층 촬영의 Protocol은 관전압 120 kVp, 관전류 150 mAs, pitch 1 mm, Increment 0.7 mm, Kernel값은 B60S Sharp을 사용하였다. 영상평가는 정형외과 전문의 1명과 영상의학과 전문의 1명이 MR과 CT modality에서 Hip joint articular transverse ligament의 6 o’clock을 중심으로 superior을 12 o’clock, Labrum의 전면을 3 o’clock, 반대쪽을 9 o’clock로 기술하는 clock face를 재구성한 후 11 o’clock에서 A. retinacular vessel, B. head neck junction, 12 o’clock A. Epiphyseal line, B. Cam lesion, 1,2,3,4 o’clock의 Cam lesion, Posterior Cam lesion확인 여부를 리커트(Likert scale) 5점 척도로 평가하였다(Independent t-test p<0.05). 평가자간 신뢰도 검증은 Cohen’s weighted Kappa 검증을 이용하여 일치성 검증을 하였다. 결 과 : 영상의 정성적 평가를 위한 리커드 척도 결과 11 o’clock A. retinacular vessel MR 평균 값 3.69±1.0, CT 평균값 2.8±0.78이며 통계적으로 유의하였다(p<0.001). B. head neck junction은 두 평가자간 차이가 없었다(p<0.416). 12 o’clock A. Epiphyseal line MR 평균값 3.54±1.00, CT 평균값 4.5±0.62이었다(p<0.000). B. Cam lesion은 두 평가자간 차이가 없었다(p<0.532). 1,2,3,4 o’clock 의 Cam lesion과 Posterior Cam lesion은 통계적으로 유의하지 않았다(p<0.656, p<0.658). weighted Kappa 검증 결과 11 o’clock A. retinacular vessel CT K값이 0.663으로 가장 낮은 일치도였으며, 각각의 평가 항목의 일치도 평가 결과 매우 높은 결과로 두 평가자간 높은 신뢰도를 보여주었다. 결 론 : 대퇴골두 충돌 증후군의 진단과 관절경을 적용하기 위하여 시행하는 CT 3D-Hip 검사는 MRI 3D clock face 재구성 기법으로 대체 가능하며, 이로 인해 불필요한 환자의 피폭선량을 최소화 할 수 있다. 또한 Cam lesion에 대한 표준화된 영상을 제시함으로써 고관절 수술 시 의료진에게 신뢰할 수 있는 영상을 제공하여 수술 전효과적인 계획을 수립할 수 있을 것으로 사료된다

목 적 : Multi echo Dixon을 기반으로 한 PDFF(Proton Density Fat Fraction) 기법을 이용하여 넓은 간 영역의 지방 함량을 계산하고 자기공명분광법(MRS)과 비교 분석하여 불균질 적으로 침착된 지방간에서의 유용성을 입증함에 목적을 두고 있다. 대상 및 방법 : 2013년 2월부터 7월까지 본원에서 복부 자기공명 영상검사를 시행한 환자 142명(남: 97, 여: 45, 평균연령: 57.9세)을 대상으로 분석하였다. MR System은 3.0T Magnetom Tim Verio(Siemens Healthcare, Germany)를 사용하여 Multi echo Dixon(3D VIBE DIXON), MRS(Single voxel high speed T2 corrected multiple echo 1H-MR spectroscopy) 기법을 시행하였다. Multi echo Dixon의 영상변수는 TR은 9.2msec이고 TE는 1.23, 2.46, 3.69, 4.92, 6.15, 7.38msec이며 Slice thickness는 4mm, Matrix: 165×256, FOV: 315×420이며, MRS에서 TR은 3,000msec 이고 TE는 12, 24, 36, 48, 72msec, Voxel size: 30×30×30mm를 사용하여 각각의 영상을 획득하였다. 획득한 PDFF Fat percentage map 상의 각각의 7개의 엽에 (II-VIII) ROI를 설정하였으며(“Segmental-PDFF”), MRS의 VOI와 같은 지점에 ROI를 설정하였다(“VOI-PDFF”). 그리고 서로 다른 세 지점에 Tablet pen을 이용하여 Liver margin을 따라 ROI를 그렸다(“Free drawn-PDFF”). 지방분율 cut-off 값인 5.56%를 기준으로 T-test, Pearson’s correlation, Linear regression test, McNemar test를 이용하여 PDFF와 MRS의 상관관계 및 좌, 우엽의 지방 함유 관계와 각각의 진단적 능력에 대해 비교 분석하였다. 결 과 : Mean fat percentage는 Free-drawn PDFF(4.5%±3.7)와 VOI-PDFF(4.5%±4.1)가 MRS(4.5%±4.3)에 가장 근접한 결과 값을 보였고, 그 중 VOI-PDFF가 가장 높은 일치성을 보였다(r=0.972, r2=0.944). 또한 지방증과 비 지방증 집단에서 우엽이 좌엽보다 더 높은 지방 함유를 나타냈다(7:2). 또한 MRS는 142명 중 40명(28%)을 지방증으로 구분하였고, Free-drawn PDFF는 32명(22.5%)을 지방증으로 구분하였다. 결 론 : MRS에서는 VOI를 국소적인 곳에 위치시켜야 하기 때문에 넓은 영역에 불균질하게 분포 되어 있는 지방을 정량화함에 있어 지방분율 Cut-off 값인 5.56%를 기준으로 지방증을 진단하는데 다소 부정확 할 수 있음을 시사한다. 반면 PDFF의 Free-drawn 기법은 간 전체 영역의 지방을 정량화함으로 이러한 문제점을 보완 할 수 있다. 따라서 Reference standard로서 MRS기법을 대체 할 수 있을 것으로 사료 된다.

What is Art on the street? Is it a series of artworks or activities performed on the street? In other words, does “art on the street” refer to “Street Art” such as street performance, happening, graffiti, or wall-painting, or does it refer to “Street Furniture” which is related to “City Design” or “Environmental Design”? In a formal sense, they all belong to Art on the street. However, in this paper, I would like to use Art on the street in an even broader sense. To me, “the street” is a metaphor of “environment.” Thus Art on the street is the art related to environment; it is an environment art. Art on the street attests the expansion of the concept of art and shows a new possibility of contemporary art. It is a promising new concept of art, but we cannot ignore the misapplication of the concept that we can find at the crossroad of Art on the street and “city beautification.” Of course, Art on the street can and sometimes needs to beautify the city. However we still need to ask how to contribute to the city beautification with Art on the street and how to validate such a practice. City space is, most of all, a space that people live in. It sounds a cliché, but it is worth repeating to better understand Art on the street. When we consider the city space in terms of its system or organization, we often overlook that it is the space in which people live, and which people create. Art on the street concerns not the city itself, but the space in which people live and make relations for each other. Without taking this into account, Art on the street becomes a mere means to ‘embellish’ the city and falls prey to the logic of capital. In this paper, I critically reviewed the problems such as City Development, Spectacularization, City Environmental Design, Public Interest and City Museum. I intended to emphasize that Art on the street is produced in the cultural space of city, but it also tends to break the mold of the cultural space and seeks a new possibility. Some might argue that my claims are unrealistic because Art on the street is not an idea but a practice. While humbly accepting the objection, I hope my critical suggestions guide a more productive direction to continue our discussions of Art on the street.

In this paper, fracture behavior of high-strength SFRC with high tensile strength steel fiber was investigated. Two different steel fibers with tensile strength of 1,200 and 1,600 MPa was used in SFRC specimens. Tst results showed that fracture behavior was more ductile with increasing the steel fiber tensile strength.

In this study, the effect of compressive loading of carbon nanotube (CNT) mixed cement composites was investigated. To evaluate the electrical resistivity variation of 30%∼60% of compressive load of cement composites containing 1.0% CNT, 1.0% CNT was added to cement composites and compressive strength was calculated. The greater the change in electrical resistance to compressive load, the more vulnerable to internal conductive networks. Also, as the amount of CNT mixed increases, the electrical resistance to the load is more sensitive and it is expected to be mixed more than 1.0%.

This paper describes the mechanical properties of high strength concrete with 1,600 MPa strength steel fiber. The fiber aspect ratio and fiber volume fraction used in this study is 80 and 0.75%. The Cylindrical specimens with ∅150×300 mm and the prisms with 150×150×550 mm were mad and tested in accordance with KS F2403 and ASTM C1609. As the result, specimens with high strength fiber has superior performance then that with normal strength fiber.

This study was conducted to evaluate the effect of self-sensing performance on strain-hardening cement composite containing CNT by curing age. The mixing amount of CNT was set at 1.0%, and SHCC fibers were mixed with PE 1.0% and steel fiber 0.5%. The electrical resistance measurement for the tensile strain sensing performance was based on AC method and 4 probe methods. Test results indicated that electrical sensitivity of SHCC decreased with an increase in curing age.

In this paper, finite element analysis of high-strength SFRC with high tensile strength steel fiber was investigated. Compressive and flexural behavior was ductile when using steel fiber tensile strength 1,600 MPa. Thorenfeldt and Trilinear models were used to describe the compressive and tensile behavior. Inverse analysis was performed to construct tensile model by evaluating flexural behavior. The flexural behavior of test results were similar to analysis results.

This research uses carbon nanotubes (CNTs) that are actively used to develop convenient and systematic management of building blocks and structural performance monitoring, away from the difficulties of structural health monitoring such as RC structures. The change in electrical resistance was evaluated according to the amount of load and compressive load. Experiments were carried out with 1.0% and 2.0% CNT, and 30% and 60% compressive strength, respectively. Experimental results show that the compressive strength of CNT 2.0% is lower than the compressive strength of CNT 1.0% but is more sensitive to changes in electrical resistance due to compressive load.

This study investigates the mechanical properties of SFRC reinforced by mixing different steel fibers with compressive strength of 70 MPa. In this study, The fiber aspect ratio consist of 60 and 80 and tensile strength is 1,100 MPa used. Cylindrical specimens with a ∅150×300 mm were made fo compression test, and prismatic specimens with a 150×150×550 mm were made fo flexural and direct shear tests. Test results show that the superior compression performance was observed in SFRC with Mixing different steel fibers.

In this research, Sensing Performance in Tensile Strain of Strain-Hardening Cement Composites by Containing of Carbon nanotube have been studied. The ultimate strength and strain were improved with increasing in amounts of CNT, and fractional change in resistivity were improved when same tensile strain. and %LE were decreased with increasing in amounts of CNT.

In this study, the seismic performance of RC frames reinforced with steel plate concrete was conducted by applying steel plate concrete into the existing RC frame and RC frame in order to evaluate the seismic reinforcement effect of steel plate concrete. The results showed that the reinforced specimen with steel plate concrete showed higher strength than the existing RC frame specimen, and the time of yield was also measured later. Therefore, sufficient seismic reinforcement effect can be expected through steel plate concrete.

This paper describes the effect of tensile strength and aspect ratio of fiber on compressive and flexural toughness index of high- and normal-strength steel fiber-reinforced concrete(SFRC). For this purpose, eight types of SFRC mixtures were made and tested. Test results indicate that the compressive and flexural toughness index of SFRC increased with increasing in tensile strength and aspect ratio of steel fiber.

In this study, the cement composites incorporating Carbon Nanotube(CNT), Carbon Black(CB), and Carbon Fiber(CF) of 0.5, 1.0, and 1.5% of binder weight were evaluated to provide conductivity. In order to achieve this, compressive strength and electrical resistance were measured. As a result, the conductivity of cement composites incorporating CNTs was more sensitive than that of cement composites containing CB and CF.

The study was conducted to evaluate the penetration performance of Surface Protection Material(SPM) according to the particle size distribution of fine aggregate. The fine three types of aggregates were used, and the amounts of SPM were applied 0.13, 0.25, 0.36, and 0.51 kg/㎡. Test results indicated that the penetration depth of SPM were improved with increasing the amounts of application of SPM. And The penetration depth of SPM were improved with increasing the percentage of passing weight of size of sieve between 0 and 1.25mm.