• Proceedings of the Acoustical Society of Korea Conference
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• 1993.06a
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• pp.3-5
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• 1993

실내 음향특성의 컴퓨터 씨뮬레이션 기법은 모형실험 기법과 더불어 건축물의 음향설계 분야에서 널리 사용되는 도구이다. 본 연구에서는 건축물의 음향특성을 설계단계에 예측하기 위해 영상법에 기초한 실내음향 해석 소프트웨어를 개발하였다. 개발된 소프트웨어는 건축물의 3차원 형상모델, 벽면등 반사체의 흡음특성, 음원과 수음점의 위치 등의 데이터를 입력하면, 음선의 전파경로, 수음위치에서의 반사음 패턴, 실내 음향 특성의 평가척 (음의 명료도, 잔향시간 등)을 산출하여 출력하는 기능을 지니고 있다. 기존의 씨뮬레이션 기법이 소요 장비나 비용, 시간적 제약으로 널리 실용화되기 어려웠던 점을 고려하여 PC급에서 간편하게 활용할 수 있도록 개발하였고 음선 전차경로의 그래픽 표현, 반사음 패턴의 분석등, 건축물의 음향 설계를 위한 기능을 부여하는데 중점을 두었다.

• 한국공간정보시스템학회:학술대회논문집
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• 2007.06a
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• pp.147-155
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• 2007

본 연구는 기술개발 자체의 효과성을 개발된 기술의 시장성, 확대 보급가능성, 민간분야의 기술 로드맵과의 관계성을 도출하는 것으로 실제로 업계에서 다양한 인맥과 프로젝트의 경험을 가지고 있는 자에 의한 심층인터뷰를 근거로 한 정성적 판단과 시장조사를 통한 정량적 판단을 결합하여 멀티센서의 기술개발의 가치를 평가하는 후속 조치에 해당되는 연구이다. 직접적 측면의 산업적 파급효과는 2006년에는 시범적인 수준에서 적용된 사례를 중심으로 정리해 본 결과, 다음과 같이 요약될 수 있다. 첫째, 전문화된 기업의 경우 각자의 강점에 기반을 두어 멀티센서의 적용시장을 바라보고 있다는 점이다. 모든 소프트웨어의 생산을 서버 부분부터 웹 버전, 모바일 버전까지 모두 보유하고 있는 벡터 부분의 GIS 수준과는 달리 위성영상 및 멀티센서 분야의 소프트웨어는 대용량으로 인한 한계로, 서버중심, 웹 중심의 개발이 이루어지고 있으나 모바일 분야까지 확장되지는 않고, 차량항법장치와의 연계를 통한 확장을 꾀하는 수준이라고 요약할 수 있다. 둘째, 전문기업이 아닌 대기업의 시장분석 및 전략에 관한 부분을 요약하자면, 멀티센서와 직접적인 연관을 갖는 회사는 많지 않으나 대체로 U-city 사업 발굴 시 멀티센서가 융합기술이 요소기술로서 기여할 수 있을 것이라는 기대는 하고 있으며, 규모도 1,000억 원 대를 상회할 것으로 바라보고 있다. 셋째, 멀티센서 개발기술의 상용화 및 산업화를 위한 제거 요소 및 감소 요소, 증가 요소 및 새로이 만들어야 할 요소 등을 다차원 전략으로 제시하였으나, 전략을 구사할 기관이 산재되어 있어 제도적 차원의 뒷받침이 기술개발과 더불어 진행되어야 한다는 결론에 이르게 된다. 넷째, 개발된 4개의 기술에 대하여 KVA에서 산출한 기업평가 방식을 변형하여 적용하였는데, 위성영상과 DEM 개발기술이 87% 이상의 점수를 받아 가장 시장성 및 활용성이 높은 기술로 평가되었으며, 초다분광영상에 대한 기술은 70%를 겨우 넘는 수준에서 평가가 되었다. 멀티센서 공간영상정보 통합처리 기술 개발은 다목적 실용위성의 보유, 국가 NGIS 사업의 결과물이 상당히 축척이 되어 있고, 라이다(LiDAR) 기술의 도입을 위한 환경이 조성되었기에 다른 국가에 비해 멀티센서 기술의 적용과 산업화가 가시화 될 수 있을 것으로 기대된다. 그러나 멀티센서 자료의 수급이 용이하지 못하고, 법 제도적인 한계, 시장의 성숙도가 기대이하라는 점 등의 한계를 노정하고 있다.

• Journal of Korean Society for Geospatial Information Science
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• v.8 no.2 s.16
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• pp.47-60
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• 2000

On this study, Among the classification methods of land cover using satellite imagery, we compared the classification accuracy of Neural Network Classifier and that of Maximum Likelihood Classifier which has the characteristics of parametric and non-parametric classification method. In the assessment of classification accuracy, we analyzed the classification accuracy about testing area as well as training area that many analysts use generally when assess the classification accuracy. As a result, Neural Network Classifier is superior to Maximum Likelihood Classifier as much as 3% in the classification of training data. When ground reference data is used, we could get poor result from both of classification methods, but we could reach conclusion that the classification result of Neural Network Classifier is superior to the classification result of Maximum Likelihood Classifier as much as 10%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.3
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• pp.327-335
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• 2011

A study on the RCS of a self-manufactured active transponder, which has a manually adjustable RCS, for SAR(Synthetic Aperture Radar) external calibration and image analysis at X-band is presented in this paper. The RCS of the active transponder was comparably analyzed using the lab-test and the COSMO-SkyMed SAR system, and also precisely analyzed the difference between the adjusted and estimated RCSs. A maximum RCS of the designed and manufactured active transponder is 60 dBsm. The active transponders with 60 dBsm and the adjusted RCS of 40 dBsm were measured using the single target calibration technique(STCT) and 2D target scanning technique(2DTST). And the extracted RCS using power-spill integration technique in a SAR image was compared with the measured RCS of active transponder. The comparison results show that the measured and extracted RCSs are 59.7 dBsm, 40.2 dBsm and 57.3 dBsm, 39.2 dBsm, respectively.

• The KIPS Transactions:PartB
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• v.15B no.5
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• pp.421-434
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• 2008

As computer graphics, virtual reality and augmented reality technologies have been developed, in many application areas based on those techniques, interaction for 3D space is required such as selection and manipulation of an 3D object. In this paper, we propose a framework for a vision-based 3D interaction which enables to simulate functions of an expensive 3D mouse for a desktop environment. The proposed framework includes a specially manufactured interaction device using three-color LEDs. By recognizing position and color of the LED from video sequences, various events of the mouse and 6 DOF interactions are supported. Since the proposed device is more intuitive and easier than an existing 3D mouse which is expensive and requires skilled manipulation, it can be used without additional learning or training. In this paper, we explain methods for making a pointing device using three-color LEDs which is one of the components of the proposed framework, calculating 3D position and orientation of the pointer and analyzing color of the LED from video sequences. We verify accuracy and usefulness of the proposed device by showing a measurement result of an error of the 3D position and orientation.

• Journal of Korean Society for Geospatial Information Science
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• v.12 no.3 s.30
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• pp.51-59
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• 2004

In the study, there has been a sharp upward trend in road maintenance cost as the expansion of road networks increases. Running a pavement management system(PMS) is indispensable for efficient and scientific maintenance of the whole road networks with limited maintenance budgets. With a PMS, a maintenance plan should be drawn up after surface conditions are precisely examined and analyzed. The majority of the present PMSs are run by the fact that experts first examine surface conditions on sites, and then enter results into systems. However, considering the actual circumstances of the present time and the increase in paved road hereafter, it is inefficient that experts examine the whole paved roads in person and long-lasting PMSs can not be kept up. As a result, after analyzing the accuracy of 3-D coordinates representing road surfaces that was decided using multi orientation and digital photogrammetry, the average of standard errors turned out to be 0.0427m on the X-axis, 0.0527m on the Y-axis and 0.1539m on the Z-axis. It was found to be good enough to be put to practical use for maps drawn on scales below 1 :1000, which are being currently made and used within the country, and GIS data.

• Journal of Korea Multimedia Society
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• v.13 no.11
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• pp.1698-1705
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• 2010

In this paper, we propose a fast liver segmentation method from magnetic resonance(MR) images. Our method efficiently divides a MR image into a set of discrete objects, and boundaries based on the normalized gradient magnitude information. Then, the objects belonging to the liver are detected by using 2D seeded region growing with seed points, which are extracted from the segmented liver region of the slice immediately above or below the current slice. Finally, rolling ball algorithm, and connected component analysis minimizes false positive error near the liver boundaries. Our method was validated by twenty data sets and the results were compared with the manually segmented result. The average volumetric overlap error was 5.2%, and average absolute volumetric measurement error was 1.9%. The average processing time for segmenting one data set was about three seconds. Our method could be used for computer-aided liver diagnosis, which requires a fast and accurate segmentation of liver.

• 한국가시화정보학회:학술대회논문집
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• 2004.11a
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• pp.34-35
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• 2004

Three dimensional density distributions of impinging and eccentric flames have been investigated by digital speckle tomography. The flames have been ignited by a mixture of butane and air from a circular nozzle and impinged against a plate located at the upper side of the burner exit. For comparison with experimental data, computer synthesized phantoms of impinging and eccentric flames have been reconstructed by a developed three-dimensional multiplicative algebraic reconstruction technique (MART). The advanced reconstruction in the stagnation flow region involved the sharp change of the flow direction and pressure gradient has been developed using a cross-correlation method and new scanning technique for the speckle displacement.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.5
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• pp.585-597
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• 2009

This research aims to develop a registration method to remove the geometric inconsistency between aerial images and LIDAR data acquired from an airborne multi-sensor system. The proposed method mainly includes registration primitives extraction, correspondence establishment, and EOP(Exterior Orientation Parameters) adjustment. As the registration primitives, we extracts planar patches and intersection edges from the LIDAR data and object points and linking edges from the aerial images. The extracted primitives are then categorized into horizontal and vertical ones; and their correspondences are established. These correspondent pairs are incorporated as stochastic constraints into the bundle block adjustment, which finally precisely adjusts the exterior orientation parameters of the images. According to the experimental results from the application of the proposed method to real data, we found that the attitude parameters of EOPs were meaningfully adjusted and the geometric inconsistency of the primitives used for the adjustment is reduced from 2 m to 2 cm before and after the registration. Hence, the results of this research can contribute to data fusion for the high quality 3D spatial information.

• Journal of the Korean Society of Radiology
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• v.6 no.2
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• pp.93-98
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• 2012

Micro-computed tomography (microCT) is an important tool for preclinical vascular imaging, with micron-level resolution. This non-destructive means of imaging allows for rapid collection of 2D and 3D reconstructions to visualize specimens prior to destructive analysis such as pathological analysis. Objectives. The aim of this study was to suggest a method for ex vivo, postmortem examination of stented arterial segments with microCT. And ex vivo evaluation of stents such as bare metal or drug eluting stents on in-stent restenosis (ISR) in rabbit model was performed. The bare metal stent (BMS) and drug eluting stent (DES, paclitaxel) were implanted in the left or right iliac arteries alternatively in eight New Zealand white rabbits. After 4 weeks of post-implantation, the part of iliac arteries surrounding the stent were removed carefully and processed for microCT. Prior to microCT analysis, a contrast medium was loaded to lumen of stents. All samples were subjected to an X-ray source operating at 50 kV and 200 ${\mu}A$ by using a 3D isotropic resolution. The region of interest was traced and measured by CTAN analytical software. Objects being exposed to radiation had different Hounsfield unit each other with values of approximately 1.2 at stent area, 0.12 ~ 0.17 at a contrast medium and 0 ~ 0.06 at outer area of stent. Based on above, further analyses were performed. As a result, the difference of lengths and volumes between expanded stents, which may relate to injury score in pathological analysis, was not different significantly. Moreover, ISR area of BMS was 1.6 times higher than that of DES, indicating that paclitaxel has inhibitory effect on cell proliferation and prevent infiltration of restenosis into lumen of stent. And ISR area of BMS was higher ($1.52{\pm}0.48mm^2$) than that of DES ($0.94{\pm}0.42mm^2$), indicating that paclitaxel has inhibitory effect on cell proliferation and prevent infiltration of restenosis into lumen of stent. Though it was not statistically significant, it showed that the extent of neointema of mid-region of stents was relatively higher than that of anterior and posterior region in parts of BMS as showing cross-sectional 2-D image. suggest that microCT can be utilized as an accessorial tool for pathological analysis.