• 한국조경학회지
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• 제30권4호
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• pp.9-18
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• 2002

This study investigated the influential range of landmarks and the relationship between landmarks and cognition factor so as to offer basic data to be used for the effective use and the management of landmarks. In this study, eighteen famous landmark in Seoul were selected and analyzed. The result of this study can be summarized as follows : 1) First, eighteen determining elements of cognition factors were selected via documents survey. Second, general cognition factors of landmarks were analysed using these elements through questionnaires to specialists. As a result of factor analysis, historic cultural factor, scale factor, visual form factor, locational factor and uniqueness factor were revealed. 2) According to revealed cognition factor, eighteen landmarks are categorized into four types using MDS method via questionnaire to resident in Seoul city. These four types of landmarks are: type I that are recognized by historic cultural factor; type II that are recognized by scale factor; type III that are recognized by uniqueness factor; and type IV that are recognized by visual form factor. 3) As the result of regression, the influential range of landmarks were revealed at about a 10km radius(type I : 12km type II : whole area of Seoul city≒15km, typeIII : 8.7km, typeIV : 8.5km). 4) As a result of analysing the correlation between the influential range and the cognition factor through multiple linear regression analysis, the locational factor is the main factor affecting the influential range of landmarks in every type. The uniqueness factor comes next, which affects influential range partially. 5) Except type 1, as a result of analysing the correlation between influential range and the physical heights of landmarks, a quadratic equation is revealed, showing that the influential range of landmarks over 200 meters in height shows a radical change. Landmarks can be used as reinforcement tools of legibility, effective tools for landscape management and for the improvement of a community's image. This study on the influential range of landmarks and main cognition factor can be utilized as a landmark management plan and in urban planning, such as a new town plan.

• 디자인학연구
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• 제16권2호
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• pp.255-270
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• 2003

본 연구의 목적은 루트 커뮤니케이션(Route Communication)에서 랜드마크의 역할을 이론적인 고찰에 의해 밝히고, 기존 길찾기 연구에서 거론되지 않았던 랜드마크의 언어적 요소인 설명용이성에 대한 루트 커뮤니케이션에서의 역할을 찾는데 있다. 이 연구에서 수행된 랜드마크 분석은 랜드마크의 설명용이성(describability)을 확인하고, 랜드마크의 설명 용의성이 루트 커뮤니케이션의 전반적인 과정에서 밀접한 관계가 있다고 가설하였다. 이 연구의 가설을 증명하기 위해 버츄얼 리얼리티(Virtual Reality; H) 실험이 수행되었다. 이 실험의 독립변수는 랜드마크의 설명용이성이고, 가설을 증명하기 위해 루트 커뮤니케이션의 결과인 길찾기에서 피실험자가 소비한 총 시간 등을 측정하였다. 결과는 랜드마크의 설명용이성이 전반적인 루트 커뮤니케이션 과정에 긍정적인 영향을 준다고 보여주었다. 본 논문의 결과를 분석하여 랜드마크의 특성에 다른 언어적 특성이 존재 할것이라는 가능성을 발견하였으며, 인간 행동의 실험 도구로서 의 가상현실 시뮬레이션에 대하여 본 연구의 실험 과정을 토대로 논하고 문제점을 지적하였다. 결론적으로서, 이 연구는 실질적인 루트 커뮤니케이션을 통한 길찾기의 문제에 대한 해결방법을 모색하고 좀더 효율적인 길찾기 기능을 가진 실내 환경을 위한 전제 요소로서의 랜드마크의 실질적 기능과 가능성을 제시하였다.

• 치과방사선
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• 제27권1호
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• pp.99-106
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• 1997

The purpose of this study was to compare & to find out the variability of head film measurements (and marks identification) between Fuji computed radiographic cephalometry and conventional cephalometry. 28 Korean adults were selected. Lateral cephalometric FCR film and conventional cephalometric film of each subject was taken. Four investigators identified 24 cephalometric landmarks on lateral cephalometric FCR film and conventional cephalometric film. The comparable measurements between lateral cephalometric FCR film and conventional cephalometric film were statistically analysed. The results were as follows : 1. In FCR film & conventional film, coefficient of variation (C.V.) of 24 landmarks was taken horizonta1ly & vertically. There is no significant difference of rank order of landmarks in C.V. between two films. 2. In comparison of significant differences of landmarks variability between FCR film & conventional film, horizontal value of coefficient of variation, showed significant differences in four landmarks among twenty-four landmarks, but vertical value of coefficient of variation showed significant differences in sixteen landmarks among twenty-four landmarks. FCR film showed significantly less variability than conventional film in 17 subjects among 20(4+16) subjects that showed significant difference.

• IEIE Transactions on Smart Processing and Computing
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• 제5권3호
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• pp.178-184
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• 2016

This paper proposes a new path-finding scheme using viewpoint-invariant landmarks. The scheme introduces the concept of landmark detection in images captured with a vision sensor attached to a mobile robot, and provides landmark clues to determine a path. Experiment results show that the scheme efficiently detects landmarks with changes in scenes due to the robot's movement. The scheme accurately detects landmarks and reduces the overall landmark computation cost. The robot moves in the room to capture different images. It can efficiently detect landmarks in the room from different viewpoints of each scene. The outcome of the proposed scheme results in accurate and obstacle-free path estimation.

• 전기학회논문지
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• 제63권1호
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• pp.123-131
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• 2014

An INS/vision integrated navigation algorithm is proposed for environments with insufficient number of landmarks. In the proposed algorithm, the raw measurements on the focal plane are directly used in order to cope with the situation where the number of landmarks are not sufficient. In addition to this, the combination of landmarks, which has smallest value of DOP, is used in the update of measurement in order to improve navigation performance. In order to evaluate the performance of the proposed integrated navigation system, Monte-Carlo simulation and van test was performed. The results of the simulation and experiment show that the proposed navigation system gives better navigation performance than an INS/vision integrated navigation system which does not use the raw measurements on the focal plane and the navigation system provides navigation solutions even in environments with insufficient number of landmarks.

• Asian Spine Journal
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• 제12권6호
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• pp.1123-1126
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• 2018

Study Design: Observational study. Purpose: To assess the correlational accuracy between the traditional anatomic landmarks of the neck and their corresponding vertebral levels in Southern Chinese patients. Overview of Literature: Recent studies have demonstrated discrepancies between traditional anatomic landmarks of the neck and their corresponding cervical vertebra. Methods: The center of the body of the hyoid bone, the upper limit of the lamina of the thyroid cartilage, and the lower limit of the cricoid cartilage were selected as representative surface landmarks for this investigation. The corresponding vertebral levels in 78 patients were assessed using computed tomography. Results: In both male and female patients, almost none of the anatomical landmarks demonstrated greater than 50% correlation with any vertebral level. The most commonly corresponding vertebra of the hyoid bone, the lamina of the thyroid cartilage, and the cricoid cartilage were the C4 (47.5%), C5 (35.9%), and C7 (42.3%), respectively, which were all different from the classic descriptions in textbooks. The vertebral levels corresponding with the thyroid and cricoid cartilage were significantly different between genders. Conclusions: The surface landmarks of the neck were not accurate enough to be used as the sole determinant of vertebral levels or incision sites. Intra-operative fluoroscopy is necessary to accurately locate each of the cervical vertebral levels.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.264-264
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• 2000

In this paper, we propose a method to automatically extract stable visual landmarks from observed data for a mobile robot with stereo vision system. The robot selects as stable landmarks vertical line segments which are distinct and on planar surfaces, because they are expected to be observed reliably from various view-points. When the robot moves, it uses several, less uncertain landmarks for estimating its motion. Experimental results in real scenes show the validity of the proposed method.

• Imaging Science in Dentistry
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• 제45권4호
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• pp.213-220
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• 2015

Purpose: The aim this study was to compare the accuracy of orthodontists and dentomaxillofacial radiologists in identifying 17 commonly used cephalometric landmarks, and to determine the extent of variability associated with each of those landmarks. Materials and Methods: Twenty digital lateral cephalometric radiographs were evaluated by two groups of dental specialists, and 17 cephalometric landmarks were identified. The x and y coordinates of each landmark were recorded. The mean value for each landmark was considered the best estimate and used as the standard. Variation in measurements of the distance between landmarks and measurements of the angles associated with certain landmarks was also assessed by a subset of two observers, and intraobserver and interobserver agreement were evaluated. Results: Intraclass correlation coefficients were excellent for intraobserver agreement, but only good for interobserver agreement. The least reliable landmark for orthodontists was the gnathion (Gn) point (standard deviation [SD], 5.92 mm), while the orbitale (Or) was the least reliable landmark (SD, 4.41 mm) for dentomaxillofacial radiologists. Furthermore, the condylion (Co)-Gn plane was the least consistent (SD, 4.43 mm). Conclusion: We established that some landmarks were not as reproducible as others, both horizontally and vertically. The most consistently identified landmark in both groups was the lower incisor border, while the least reliable points were Co, Gn, Or, and the anterior nasal spine. Overall, a lower level of reproducibility in the identification of cephalometric landmarks was observed among orthodontists.

• Imaging Science in Dentistry
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• 제51권3호
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• pp.299-306
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• 2021

Purpose: This study aimed to propose a fully automatic landmark identification model based on a deep learning algorithm using real clinical data and to verify its accuracy considering inter-examiner variability. Materials and Methods: In total, 950 lateral cephalometric images from Yonsei Dental Hospital were used. Two calibrated examiners manually identified the 13 most important landmarks to set as references. The proposed deep learning model has a 2-step structure-a region of interest machine and a detection machine-each consisting of 8 convolution layers, 5 pooling layers, and 2 fully connected layers. The distance errors of detection between 2 examiners were used as a clinically acceptable range for performance evaluation. Results: The 13 landmarks were automatically detected using the proposed model. Inter-examiner agreement for all landmarks indicated excellent reliability based on the 95% confidence interval. The average clinically acceptable range for all 13 landmarks was 1.24 mm. The mean radial error between the reference values assigned by 1 expert and the proposed model was 1.84 mm, exhibiting a successful detection rate of 36.1%. The A-point, the incisal tip of the maxillary and mandibular incisors, and ANS showed lower mean radial error than the calibrated expert variability. Conclusion: This experiment demonstrated that the proposed deep learning model can perform fully automatic identification of cephalometric landmarks and achieve better results than examiners for some landmarks. It is meaningful to consider between-examiner variability for clinical applicability when evaluating the performance of deep learning methods in cephalometric landmark identification.

• 한국실내디자인학회논문집
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• 제37호
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• pp.119-128
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• 2003

The goal of this study was to understand human behavior in reference to wayfinding during emergency situations. In an emergency situation, it is recommended that evacuees follow instructions about an available exit rather than finding their way on their own. Wayfinding studies suggest that landmarks affect entire route communication. Landmark analysis for this study Identified describability, e.g., name and simplicity of landmark features. A virtual reality (VR) simulation test was conducted to examine the effect of landmarks on wayfinding. The independent variables were landmarks, smoke. Results suggest that the describability of landmarks is a positive Influence to route communication. Findings from this study, however, Indicates that smoke condition did not significantly affect participants' wayfinding.