• 한국지형공간정보학회:학술대회논문집
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• 2004.10a
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• pp.25-31
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• 2004

To obtain the 3-D coordinates of the urban roads from aerial images, the accurate matching technique in road areas is required. In this paper, we suggest the relational matching method that is performed by comparison of relationships of road pavement markings after they are extracted from aerial images using geometric properties and spatial relationships of the pavement markings. Relational matching requires not only high level description of features but also the solution for inexact matching problems. In addition, it needs a lot of tests for the reliable final result. In this research, we described features as calculating geometric properties of the pavement markings, suggested the solution for inextact matching problems, and performed tests to decide whether the result is acceptable or not, which use the property that road areas are flat. In order to evaluate the accuracy of matching, we made a visual evaluation and compared the result of this technique with those measured by analytical photogrammetry.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.1
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• pp.51-56
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• 2003

The main goal of existing mobile robot system was a complete autonomous navigation and the vision information was just used as an assistant way such as monitoring For this reason, the researches have been going towards sophistication of autonomousness gradually and the production costs also has been risen. However, it is also important to control remotely an inexpensive mobile robot system which has no intelligence at all. Such systems may be much more effective than fully autonomous systems in practice. Visual information from a simple camera and distance information from ultrasonic sensors are used for this system. Collision avoidance becomes the most important problem for this system. In this paper, we developed a force feedback joystick to control the robot system remotely with collision avoiding capability. Fuzzy logic is used for the algorithm in order to implement the expert s knowledge intelligently. Some experimental results show the force feedback joystick werks very well.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.345-345
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• 2020

우리나라는 물산업 강국 도약을 위한 글로벌 경쟁력을 갖추기 위해 2015년 세계물포럼 이후 복합 수재해 대응과 능동적 하천관리 분야가 중요시되고 있다. 기존의 하천관리는 수위관측소 및 하도계획을 중심으로 이루어져왔으나 최근에는 항공측량, 드론 등 원격관리시스템에 기반을 둔 하천 통로에 대한 입체적인 3차원 관리로의 인식 전환이 고려되는 추세이다. 대부분 수위 및 하도를 중심으로 한 조사방식은 계측장비, 인력, 시간 등 많은 소요비용이 필요하게 되어 급변하는 하천 공간 조사 기술로 제한적 요소가 많아 현재의 하천조사 시스템으로는 하천관리에 필요한 데이터를 환경변화에 맞추어 신속하고 정확하게 취득하기가 어려운 실정으로 하천관리 고도화를 위해 필요한 자료를 적기에 신속하고 효율적으로 구축할 수 있는 기술 개발 필요한 실정이다. 사회 환경의 발달로 급변하는 환경에 맞는 적정한 하천관리를 위해서는 유역 및 하천에 대한 수문정보 생산 및 하상변동조사가 필요하고 첨단기술(ICT)을 활용하여 조사의 효율성, 안전성 및 정확성을 높일 필요성이 있다. 한편, 하천유역조사는 하천유역에 대한 다양한 정보 수집을 목표로 하나 그간 유역조사에 대한 체계적인 연구가 이루어지지 않아 수요자의 요구 자료 제공이 미흡한 실정이다. 최근 수심, 하상, 하천재료 등 하천법에 규정된 측량은 현장 직접계측을 통해 실시되고 있으며 측량의 공간적·시간적 범위의 변동으로 기존 방식의 비용이 급증하게 되어 신기술을 통한 효율화가 필요한 실정이다. 현재 하천조사를 위해 위성 및 유인항공기 등 다양한 방법이 활용되고 있으나 고빙용을 수반하고 위성영상은 공간해상도가 낮아 폭이 좁은 하천에 적용하는데 한계가 있다. 또한, 폭이 좁고 길게 형성된 하천의 특성상 항공측량 보다 드론이 효율적으로 드론에 레이저 광선으로 지형을 측량하는 장비를 탑재해 3차원 지형을 측량하는 방법이 유리하다. 따라서 본 연구에서는 동진강 상류 하천을 대상으로 드론을 활용할 경우 투입인력 및 소요시간 절감, 장비 및 인력 진입 불가지역에 대한 정보획득, 높은 공간해상도, 항공측량 대비 경제성이 높은 것으로 판단되어 드론을 활용하여 하천지형 모니터링을 실시하여 유역관리 및 수질모델링에 필요한 지도 생성 및 유역의 공간 정보를 획득하여 향후 유역관리 모형의 기초자료로 활용하고자 하였다.

• Korean Journal of Heritage: History & Science
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• v.43 no.3
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• pp.306-333
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• 2010

Previous studies on Wolseong fortress have focused on capital system of Silla Dynasty and on the recreation of Wolseong fortress due to the excavations in and around Wolseong moat. Since the report on the Geographical Survey of Wolseong fortress was published and GPR survey in Wolseong fortress was executed as a trial test in 2004, the academic interest in the site has now expanded to the inside of the fortress. From such context, the preliminary research on the fortress including geophysical survey had been commenced. GPR survey had been conducted for a year from March, 2007. The principal purpose of the recent 3D GPR survey was to provide visualization of subsurface images of the entire Wolseong fortress area. In order to obtain 3D GPR data, dense profile lines were laid in grid-form. The total area surveyed was $112,535m^2$. Depth slice was applied to analyse each level to examine how the layers of the remains had changed and overlapped over time. In addition, slice overlay analysis methodology was used to gather reflects of each depth on a single map. Isolated surface visualization, which is one of 3D analysis methods, was also employed to gain more in-depth understanding and more accurate interpretations of the remain The GPR survey has confirmed that there are building sites whose archaeological features can be classified into 14 different groups. Three interesting areas with huge public building arrangement have been found in Zone 2 in the far west, Zone 9 in the middle, and Zone 14 in the far east. It is recognized that such areas must had been used for important public functions. This research has displayed that 3D GPR survey can be effective for a vast area of archaeological remains and that slice overlay images can provide clearer image with high contrast for objects and remains buried the site.

• Journal of Broadcast Engineering
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• v.19 no.4
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• pp.533-546
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• 2014

This paper presents a method for a hybrid (color and depth) camera system construction using a photogrammetric technology. A TOF depth camera is efficient since it measures range information of objects in real-time. However, there are some problems of the TOF depth camera such as low resolution and noise due to surface conditions. Therefore, it is essential to not only correct depth noise and distortion but also construct the hybrid camera system providing a high resolution texture map for generating a 3D model using the depth camera. We estimated geometry of the hybrid camera using a traditional relative orientation algorithm and performed texture mapping using backward mapping based on a condition of collinearity. Other algorithm was compared to evaluate performance about the accuracy of a model and texture mapping. The result showed that the proposed method produced the higher model accuracy.

• The Journal of Korean Society for Radiation Therapy
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• v.18 no.1
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• pp.35-41
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• 2006

Purpose: A various find of radiotherapy treatment plans have been made to determine appropriate doses for breasts, chest walls and loco-regional lymphatics in the radiotherapy of breast cancers. The aim of this study was to evaluate the optimum radiotherapy plan technique method by analyzing dose distributions qualitatively and quantitatively. Materials and Methods: To evaluate the optimum breast cancer radiotherapy plan technique, the traditional method(two dimensional method) and computed tomography image are adopted to get breast volume, and they are compared with the three-dimensional conformal radiography (3DCRT) and the intensity modulated radiotherapy (IMRT). For this, the regions of interest (ROI) such as breasts, chest walls, loco-regional lymphatics and lungs were marked on the humanoid phantom, and the computed tomography(Volume, Siemens, USA) was conducted. Using the computed tomography image obtained, radiotherapy treatment plans (XiO 5.2.1, FOCUS, USA) were made and compared with the traditional methods by applying 3DCRT and IMRT. The comparison and analysis were made by analyzing and conducting radiation dose distribution and dose-volume histogram (DVH) based upon radiotherapy techniques (2D, 3DCRT, IMRT) and point doses for the regions of interest. Again, treatment efficiency was evaluated based upon time-labor. Results: It was found that the case of using 3DCRT plan techniques by getting breast volume is more useful than the traditional methods in terms of tumor delineation, beam direction and confirmation of field boundary. Conclusion: It was possible to present the optimum radiotherapy plan techniques through qualitative and quantitative analyses based upon radiotherapy plan techniques in case of breast cancer radiotherapy. However, further studies are required for the problems with patient setup reproducibility arising from the difficulties of planning target volume (PVT) and breast immobilization in case of three-dimensional radiotherapy planning.

• Radiation Oncology Journal
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• v.18 no.2
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• pp.107-113
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• 2000

Purpose : The goal of this study 닌as to improve the accuracy of three-dimensional conformal radiotherapy (3-D CRT) by measuring the treatment setup error and physiological movement of liver based on the analysis of images which were obtained by electronic portal imaging device (EPID). Materials and Methods : For 10 patients with hepatocellular carcinoma, 4-7 portal images were obtained by using EPID during the radiotherapy from each patient daiiy. We analyzed the setup error and physiological movement of liver based on the verification data. We also determined the safety margin of the tumor in 3-D CRT through the analysis of physiological movement. Results : The setup errors were measured as 3mm with standard deviation 1.70 mm in x direction and 3.7 mm with standard deviation 1.88 mm in y direction respectively. Hence, deviation were smaller than 5mm from the center of each axis. The measured range of liver movement due to the physiological motion was 8.63 mm on the average. Considering the motion of liver and setup error, the safety margin of tumor was at least 15 mm. Conclusion : EPID is a very useful device for the determination of the optimal margin of the tumor, and thus enhance the accuracy and stability of the 3-D CRT in patients with hepatocellular carcinoma.

• Progress in Medical Physics
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• v.10 no.2
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• pp.63-71
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• 1999

For the purpose of utilization in 3-D conformal radiotherapy and whole body radiosurgery, the Whole Body 3-Dimensional Topographic Radiation Therapy System has been developed. Whole body frame was constructed in order to be installed on the couch. Radiopaque catheters were engraved on it for the dedicated coordinate system and a MeV-Green immobilizer was used for the patient setup by the help of side panels and plastic rods. By designing and constructing the whole body frame in this way, geometrical limitation to the gantry rotation in 3-D conformal radiotherapy could be minimized and problem which radiation transmission may be altered in particular incident angles was solved. By analyzing CT images containing information of patient setup with respect to the whole body frame, localization and coordination of the target is performed so that patient setup error may be eliminated between simulation and treatment. For the verification of setup, the change of patient positioning is detected and adjusted in order to minimize the setup error by means of comparison of the body outlines using 3 CCTV cameras. To enhance efficiency of treatment procedure, this work can be done in real time by watching the change of patient setup through the monitor. The method of image subtraction in IDL (Interactive Data Language) was used to visualize the change of patient setup. Rotating X-ray system was constructed for detecting target movement due to internal organ motion. Landmark screws were implanted either on the bones around target or inside target, and variation of target location with respect to markers may be visualized in order to minimize internal setup error through the anterior and the lateral image information taken from rotating X-ray system. For CT simulation, simulation software was developed using IDL on GUI(Graphic User Interface) basis for PC and includes functions of graphic handling, editing and data acquisition of images of internal organs as well as target for the preparation of treatment planning.

• The korean journal of orthodontics
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• v.36 no.6
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• pp.412-421
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• 2006

Objective: The result of finite element analysis depends on material properties, structural expression, density of element, and boundar or loading conditions. To represent proper elastic behavior, a finite element model was made using Hounsfield unit (HU) values in CT images. Methods: A 13 year 6 month old male was used as the subject. A 3 dimensional visualizing program, Mimics, was used to build a 3D object from the DICOM file which was acquired from the CT images. Model 1 was established by giving 24 material properties according to HU. Model 2 was constructed by the conventional method which provides 2 material properties. Protraction force of 500g was applied at a 45 degree downward angle from Frankfort horizontal (FH) plane. Results: Model 1 showed a more flexible response on the first premolar region which had more forward and downward movement of the maxillary anterior segment. Maxilla was bent on the sagittal plane and frontal plane. Model 2 revealed less movement in all directions. It moved downward on the anterior part and upward on the posterior part, which is clockwise rotation of the maxilla. Conclusion: These results signify that different outcomes of finite element analysis can occur according to the given material properties and it is recommended to use HU values for more accurate results.

• Journal of the HCI Society of Korea
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• v.8 no.2
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• pp.21-27
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• 2013

Recently, the use of floating hologram has increased in many different aspects, such as exhibitions, education, advertisements, and so on. Especially, the floating hologram that makes use of half-mirror is widely used. Nevertheless, half-mirror, unfortunately, cannot lead users to the perfect three dimensional hologram experience. Even though it can make the vision look to be up on the air, it does not have the capacity to display itself up on the air, which is the ultimate goal of hologram. In addition, it looks inconsistent when a real object is located behind the half-mirror in order to show the convergence of the two (object and the half-mirror). In this paper, we did the study on comparison of 3D space perception for the stereoscopic AR holography. At first, we applied stereoscopic technology to the half-mirror hologram system for the accurate and realistic AR environment. Then, the users can feel as if the real 3D object behind half-mirror and the reflected virtual image are converged much better in the 3D space. Furthermore, by using depth camera, the location and direction of graphics can be controlled to change depending on the user's point of view. This is the effective way to produce augmented stereoscopic images simply and accurately through half-mirror film without any additional devices. What we saw from the user test were applying 3D images and user interaction leads the users to have 3D spatial awareness and realism more effectively and accurately.