• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.73-74
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• 2010

• Korean Institute of Interior Design Journal
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• v.24 no.6
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• pp.30-37
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• 2015

This study has the purpose to investigate the landscape plans focused on the public sector housing complexes in the Seoul Metropolitan Area in the 2000s. The targeted subjects of this study are 24 districts conducted by the Corporation, and the spatial extent is limited to Seoul metropolitan area. The scope of the research is limited to the public sector, because this sector has been conducted preferentially for public needs rather than the development profit, and has positively reflected the will "pre plan - post development". In view of the study methodologies, this study examined the transition process in Korea housing complex and analyzed the design reports to extract the key planning concepts and planning methods of landscape planning. The main concepts of landscape planning analyzed in this study were urban landscape, natural landscape, streetscape, architectural landscape, axis for viewing, landmark, skyline and landscape by areas. The key planning methods of landscape planning were landmark, which is a point landscape element, axis for viewing and skyline, which are linear landscape elements, landscape by areas which is an area landscape element, and finally complex landscape, walking landscape and nightscape, which are three-dimensional landscape elements.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.3
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• pp.236-242
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• 2010

A GNSS/INS integration system can not provide navigation solutions if there are no available satellites. To overcome this problem, a vision sensor is integrated with this system. Since generally a vision aided integration system uses only feature point to compute navigation solutions, it has a problem in observability. In this case, additional landmarks, which is priory known points, can improve the observability. In this paper, the observability is evaluated using TOM/SOM matrix and Eigenvalues. There are always the observability problems in the feature-point-only case, but the landmark-use case is fully observable after the $2^{nd}$ update time. Consequently the landmarks ensure full observability, so the system performance can be improved.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.5
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• pp.397-403
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• 2001

Purpose: The purpose of this study was to evaluate the postoperative stability of LeFort I osteotomy in two-jaw surgery of skeletal class III malocclusion and to help the establishment of treatment planning in patients with a skeletal class III malocclusion in the future. Materials and Methods: The lateral cephalograms of 14 patients who had been underwent two-jaw surgery via one-piece LeFort I osteotomy were traced and the landmarks were identified. Repeated tracings and construction of reference planes were done. Comparisons were made from the immediate postoperative to late postoperative results of each landmarks on the horizontal and vertical directions. Conclusions: 1. The horizontal changes of landmark ANS, point A, PNS and Mx6Rt between immediate postoperative to late postoperative data were statistically insignificant(p>0.05). 2. The vertical changes of landmark ANS, point A, PNS, Mx6Cr and Mx6Rt between immediate postoperative to late postoperative data were statistically insignificant(p>0.05). 3. The horizontal change of landmark Mx6Cr between immediate postoperative to late postoperative data was statistically significant(p<0.05). 4. Results showed that it was stable that one-piece LeFort I osteotomy in two-jaw surgery of skeletal class III malocclusion.

• The korean journal of orthodontics
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• v.54 no.1
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• pp.48-58
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• 2024

Objective: To quantify the effects of midline-related landmark identification on midline deviation measurements in posteroanterior (PA) cephalograms using a cascaded convolutional neural network (CNN). Methods: A total of 2,903 PA cephalogram images obtained from 9 university hospitals were divided into training, internal validation, and test sets (n = 2,150, 376, and 377). As the gold standard, 2 orthodontic professors marked the bilateral landmarks, including the frontozygomatic suture point and latero-orbitale (LO), and the midline landmarks, including the crista galli, anterior nasal spine (ANS), upper dental midpoint (UDM), lower dental midpoint (LDM), and menton (Me). For the test, Examiner-1 and Examiner-2 (3-year and 1-year orthodontic residents) and the Cascaded-CNN models marked the landmarks. After point-to-point errors of landmark identification, the successful detection rate (SDR) and distance and direction of the midline landmark deviation from the midsagittal line (ANS-mid, UDM-mid, LDM-mid, and Me-mid) were measured, and statistical analysis was performed. Results: The cascaded-CNN algorithm showed a clinically acceptable level of point-to-point error (1.26 mm vs. 1.57 mm in Examiner-1 and 1.75 mm in Examiner-2). The average SDR within the 2 mm range was 83.2%, with high accuracy at the LO (right, 96.9%; left, 97.1%), and UDM (96.9%). The absolute measurement errors were less than 1 mm for ANS-mid, UDM-mid, and LDM-mid compared with the gold standard. Conclusions: The cascaded-CNN model may be considered an effective tool for the auto-identification of midline landmarks and quantification of midline deviation in PA cephalograms of adult patients, regardless of variations in the image acquisition method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3D
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• pp.393-400
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• 2006

This study is intended to examine the characteristics of driver in the use of guide sign in urban areas. The good and bad points about guide sign based on landmark point and guide sign based on street name are demonstrated, and driver's preference between them are studied. The questionnaires given to general persons deal with general guide signs and road maps, and are designed to see if they can find out current location on the road map with guide sign. According to the results, drivers prefer guide sign based on street name to guide sign based on landmark. And guide sign based on street name took less time to find current location than with guide sign based on landmark.

• The Korean Journal of Pain
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• v.24 no.3
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• pp.141-145
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• 2011

Background: Stellate ganglion block is usually performed at the transverse process of C6, because the vertebral artery is located anterior to the transverse process of C7. The purpose of this study is to estimate the location of the transverse process of C6 using the cricoid cartilage in the performance of stellate ganglion block. Methods: We reviewed cervical lateral neutral-flexion-extension views of 48 patients who visited our pain clinic between January and June of 2010. We drew a horizontal line at the surface of the cricoid cartilage in the neutral and extension views of cervical lateral x-rays. We then measured the change in the shortest distance from this horizontal line to the lowest point of the transverse process of C6 between the neutral and extension views. Results: There was a statistically significant difference in the shortest distance from the horizontal line at the surface of the cricoid cartilage to the lowest point of transverse process of C6 between neutral position and neck extension position in both males and females, and between males and females in both neutral position and neck extension position. The cricoid cartilage level was 4.8 mm lower in males and 14.4 mm higher in females than the lowest point of transverse process of C6 in neck extension position. Conclusions: Practitioners should recognize that the cricoid cartilage has cephalad movement in neck extension. In this way, the cricoid cartilage can be still useful as a landmark for stellate ganglion block.

• The korean journal of orthodontics
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• v.32 no.1 s.90
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• pp.59-69
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• 2002

The purpose of this study was to evaluate the reproducibility of lateral cephalometric landmarks according to radiographic image enhancement, and to contribute to the identification of cephalometric landmarks. Lateral cephalograms of ten individuals were taken and stored into computer. The images were then enhanced up to four grades by Quick Ceph Image Pro$^{TM}$ on condition that the gray-scale equalization number was 50 and the detail enhancement number was 50. After thirty two landmarks were identified on monitor images by five observers, the deviations from the mean, the distances estimated between identified points and the mean point of five identified points, were evaluated for each landmark at each enhancement grade. Through the statistical analysis, following results were obtained. 1. In case of unenhanced radiographic images, the inter-observer reproducibility of the landmarks showed a large variation. 2. The comparison of deviation from the mean according to the degree of radiographic image enhancement for each landmark showed that the inter-observer reproducibility was significantly different at 5 landmarks. 3. The landmark of pterygomaxillary fissure showed higher reproducibility at enhancement grade 1 and 2 images than at unenhanced images. So did the landmark of posterior nasal spine at enhancement grade 1 images, and the landmark of menton at enhancement grade 2, 3 and 4 images respectively. The above results suggest that the reproducibility of some landmarks can be increased by radiographic image enhancement during the identification of the lateral cephalometric landmarks on the monitor.

• The korean journal of orthodontics
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• v.52 no.4
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• pp.287-297
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• 2022

Objective: To investigate the pattern of accuracy change in artificial intelligence-assisted landmark identification (LI) using a convolutional neural network (CNN) algorithm in serial lateral cephalograms (Lat-cephs) of Class III (C-III) patients who underwent two-jaw orthognathic surgery. Methods: A total of 3,188 Lat-cephs of C-III patients were allocated into the training and validation sets (3,004 Lat-cephs of 751 patients) and test set (184 Lat-cephs of 46 patients; subdivided into the genioplasty and non-genioplasty groups, n = 23 per group) for LI. Each C-III patient in the test set had four Lat-cephs: initial (T0), pre-surgery (T1, presence of orthodontic brackets [OBs]), post-surgery (T2, presence of OBs and surgical plates and screws [S-PS]), and debonding (T3, presence of S-PS and fixed retainers [FR]). After mean errors of 20 landmarks between human gold standard and the CNN model were calculated, statistical analysis was performed. Results: The total mean error was 1.17 mm without significant difference among the four time-points (T0, 1.20 mm; T1, 1.14 mm; T2, 1.18 mm; T3, 1.15 mm). In comparison of two time-points ([T0, T1] vs. [T2, T3]), ANS, A point, and B point showed an increase in error (p < 0.01, 0.05, 0.01, respectively), while Mx6D and Md6D showeda decrease in error (all p < 0.01). No difference in errors existed at B point, Pogonion, Menton, Md1C, and Md1R between the genioplasty and non-genioplasty groups. Conclusions: The CNN model can be used for LI in serial Lat-cephs despite the presence of OB, S-PS, FR, genioplasty, and bone remodeling.

• Journal of Korean Neurosurgical Society
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• v.42 no.1
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• pp.35-41
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• 2007

Objective : Determining the location of paraclinoid aneurysms for microsurgery is important for selecting treatment options, especially when deciding on the release of the dural ring in direct clipping. We examined the reliability of using the optic strut as an anatomical landmark for evaluating the location of paraclinoid aneurysms. Methods : Cadaveric dissection was performed to establish the relationship of the optic strut to the dural ring. Results from these anatomic studies were compared with the three-demensional computed tomographic angiographic [3D-CTA] findings of nine patients with ten paraclinoid aneurysms between May 2004 and October 2005. These, 3D-CTA results were then compared with intraoperative findings. Results : The inferior boundary of the optic strut accurately localized the point at the proximal dural ring in cadaveric study. The optic strut and its relationship to the aneurysms was well observed on the multiplanar reformats of 3D-CTA. During microsurgery, nine of ten aneurysms were verified to arise from distal to the upper surface of the optic strut. Two aneurysms that had arisen between the inferior and superior boundary of the optic strut were observed to lie within the carotid cave. One aneurysm which had arisen at the inferior boundary of the optic strut and directed inferiorly was observed to lie within the cavernous sinus just after the release of the proximal ring. Conclusion : The optic strut, as identified with multiplanar reformats of 3D-CTA, provided a reliable anatomic landmark for the proximal rings and an important information about the location of aneurysms around the anterior clinoid process (ACP). Therefore, 3D-CTA and the optic strut could become an invaluable tool and a landmark in the assessment of the location of paraclinoid aneurysms for microsurgery.