• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.2
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• pp.115-131
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• 2000

In the study of craniofacial deformity, it is very important that identifying the factor which can affect the morphology and which is closely related to the morphology, because it can not only improve the comprehension of growth and developmental process but also be applied in growth prediction and treatment modality. Several investigators have already mentioned the characterstics of head posture and airway space in relations to morphologic difference. But it is very meaningful work in clarifying the correlation between morphology, head posture and airway space that observing the change of head posture after morplologic change caused by operation and the change of airway space after same procedure. To investigate above correlation, I selected normal group which is consisted of 43 adults and mandibular prognathism group which is consisted of 47 adults who had been operated by sagittal split ramus osteotomy and were followed up more than 1 year. With their lateral skull radiograghs, reference lines which can evaluate each measuring points and areas without effect of postural change were first determined. And using above reference lines, change of airway space, positional change of tongue and hyoid, change of cranial and cervical angulations were measured. The results obtained from the study were as follows 1. In the change of head posture, the position of tongue and hyoid neighboring to pharynx is more closely related to the reference line of cervical column than to reference line of cranium. 2. After mandibular setback operation, the airway dimension was decreased to 81.6% of preoperative state at 1 month postoperatively and was slightly increased to 89.7% at 1 year postoperatively. 3. Posterior movement of tongue plays important role in decrease of airway dimension and inferior movement of hyoid was closely correlated with posterior movement of tongue. 4. Postoperative anterior movement of mandible, namely, morphologic relapse had correlation with relapse phenomenon of airway dimension. 5. Craniocervical angulation increased postoperatively. Especially in the postoperative early state, there was increased foreward inclination of cervical angulation rather than increase of cranial angulation. But at postoperative 1 year it was observed that cervical inclination was returned to preoperative state and cranial angulation was increased gradually. 6. Increase rate of airway dimension was correlated with the increase of cranial angulation from postoperative 1 month to 1 year. In conclusion, relapse tendency of airway dimension following increase of cranial angulation was found after mandibular setback operation and it is considered that increase of cranial angulation is one of compensatory mechanism in airway maintenance.

• Journal of Cadastre & Land InformatiX
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• v.51 no.2
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• pp.73-82
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• 2021

According to the government's announcement of the safety management enhancement policy for small and medium-sized private construction sites, the subject of mandatory CCTV installation has been expanded from large construction sites to small and medium-sized construction sites. However, since the existing CCTV at construction sites has been used for simple control for safety management, so research is needed for monitoring of construction sites. Therefore, in this study, three vanishing points were calculated based on a single image taken with a monocular camera, and then a camera matrix containing interior orientation parameters information was determined. And the accuracy was verified by calculating the height of the target object from the height of the reference object. Through height determination experiments using vanishing points based on a monocular camera, it was possible to determine the height of target objects only with a single image without separately surveying of ground control points. As a result of the accuracy evaluation, the root mean square error was ±0.161m. Therefore, it is determined that the progress of construction work at the construction sites can be monitored through the single image taken using the single camera.

• Korean Journal of Remote Sensing
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• v.34 no.6_3
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• pp.1329-1350
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• 2018

There have been many applications to observe Earth using synthetic aperture radar (SAR) since it could acquire Earth observation data without reference to weathers or local times. However researches about digital map generation using SAR have hardly been performed due to complex raw data processing. In this study, we suggested feasibility of producing digital map using SAR stereo images. We collected two sets, which include an ascending and a descending orbit acquisitions respectively, of KOMPSAT-5 stereo dataset. In order to suggest the feasibility of digital map generation from SAR stereo images, we performed 1) rational polynomial coefficient transformation from radar geometry, 2) digital resititution using KOMPSAT-5 stereo images, and 3) validation using digital-map-derived reference points and check points. As the results of two models, root mean squared errors of XY and Z direction were less than 1m for each model. We discussed that KOMPSAT-5 stereo image could generated 1:25,000 digital map which meets a standard of the digital map. The proposed results would contribute to generate and update digital maps for inaccessible areas and wherever weather conditions are unstable such as North Korea or Polar region.

• Journal of Korean Elementary Science Education
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• v.42 no.4
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• pp.538-559
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• 2023

In this study, the interplay between models and theories was explored through a series of focus group discussions (FGDs) involving five experts in science education. The FGDs were held seven times, beginning with the question of what is modeling in relation to models, which is a current area of research in science education. Throughout the discussion, several key issues regarding models and modeling were addressed, with a particular emphasis on their relationship to theory. A notable finding from this study is that the participants' discussions did not converge into a single viewpoint regarding the relationship between theory and models; instead, multiple related issues emerged, leading to attempts to reframe existing concepts and seek new understanding. The study findings relate to three main areas of inquiry: What is the meaning of models or modeling? What is the nature of the relationship between models and theories?, and Is modeling possible without a foundation in theory? Particularly, the relationship between models and theories was discussed in reference to the following points: 1) Is a model to be understood as derived from theory, and is modeling the application of theory to phenomena? 2) Can a model be inferred from theory? 3) Does modeling originate from a specific, structured foundational theory (a framework of empirical knowledge), or is it to be understood through the integration of various resources without explicit reference to a foundational theory? Based on the study outcomes, implications are presented for philosophy of science and for researchers and educators working in the realm of science education.

• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1479-1488
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• 2022

Accidents in which oil spills occur intermittently in the ocean due to ship collisions and sinkings. In order to prepare prompt countermeasures when such an accident occurs, it is necessary to accurately identify the current status of spilled oil. To this end, the Coast Guard patrols the target area with a fixed-wing airplane or helicopter and checks it with the naked eye or video, but it was difficult to determine the area contaminated by the spilled oil and its exact location on the map. Accordingly, this study develops a technology for direct ortho-rectification by automatically geo-referencing aerial images collected by the Coast Guard without individual ground reference points to identify the current status of spilled oil. First, meta information required for georeferencing is extracted from a visualized screen of sensor information such as video by optical character recognition (OCR). Based on the extracted information, the external orientation parameters of the image are determined. Images are individually orthorectified using the determined the external orientation parameters. The accuracy of individual orthoimages generated through this method was evaluated to be about tens of meters up to 100 m. The accuracy level was reasonably acceptable considering the inherent errors of the position and attitude sensors, the inaccuracies in the internal orientation parameters such as camera focal length, without using no ground control points. It is judged to be an appropriate level for identifying the current status of spilled oil contaminated areas in the sea. In the future, if real-time transmission of images captured during flight becomes possible, individual orthoimages can be generated in real time through the proposed individual orthorectification technology. Based on this, it can be effectively used to quickly identify the current status of spilled oil contamination and establish countermeasures.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.5
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• pp.443-451
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• 2015

In photogrammetry, GCPs (Ground Control Points) have traditionally been used to determine EOPs (Exterior Orientation Parameters) and to produce DEM (Digital Elevation Model). The existing DEM can be used as GCPs, where the observer’s approach is a difficult area, because it is very restrictive to survey in the field. For this, DEM matching should be performed. This study proposed the fusion method using ICP (Iterative Closest Point) and RT (proposed method by Rosenholm and Torlegard, 1988) in order to improve accuracy of the DEM matching. The proposed method was compared to the ICP method to evaluate its usefulness. Pseudo reference DEM with resolution 10m, and modified DEM (random-numbers are added from 0 to 2 at height; scale is 0.9; translation is 100 meters in 3-D axes; rotation is from 10° to 50° from the reference DEM) were used in the experiment. The results proposed accuracy was highest in the matching and absolute orientation. In the case of ICP, according to rotation of the modified DEM being increased, absolute orientation error is increased, while the proposed method generally showed consistent results without increasing the error. The proposed method would be applied to matching when the DEM is modified up to 30° rotation, compared to the reference DEM, based on the results of experiments. In addition when we use Drone, this method can be utilized to identify EOPs or detect 3-D surface deformation from the existing DEM of the inaccessible area.

• Radiation Oncology Journal
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• v.14 no.1
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• pp.41-52
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• 1996

Purpose : This paper reports a dosimetric study of 88 patients treated with a combination of external radiotherapy and high dose rate ICR for FIGO stage IIB carcinoma of the cervix. The purpose is to investigate the correlation between the radiation doses to the rectum, external radiation dose to the whole pelvis, ICR reference volume, TDF BED and the incidence of late rectal complications, retrospectively. Materials and Methods : From November 1989 through December 1992, 88 patients with stage IIB cervical carcinoma received radical radiotherapy at Department of Radiation Oncology in Yonsei University Hospital. Radiotherapy consisted of 44-54 Gy(median 49 Gy) external beam irradiation plus high dose rate intracavitary brachytherapy with 5 Gy per fraction twice a week to a total dose of 30 Gy on point A. The maximum dose to the rectum by contrast(r, R) and reference rectal dose by ICRU 38(dr, DR) were calculated. The ICR reference volume was calculated by Gamma Dot 3.11 HDR planning system, retrospectively The time-dose factor(TDF) and the biologically effective dose (BED) were calculated. Results : Twenty seven($30.7\%$) of the 88 patients developed late rectal complications:12 patients($13.6\%$) for grade 1, 12 patients($13.6\%$) for grade 2 and 3 patients($3.4\%$) for grade 3. We found a significant correlation between the external whole pelvis irradiation dose and grade 2, 3 rectal complication. The mean dose to the whole pelvis for the group of patients with grade 2, 3 complication was Higher, $4093.3\pm453.1$ cGy, than that for the patients without complication, $3873.8\pm415.6$ (0.05$7163.0\pm838.5$ cGy, than that for the Patients without rectal complication, $0772.7\pm884.0$ (p<0.05). There was no correlation of the rate of grade 2, 3 rectal complication with the iCR rectal doses(r, dr), ICR reference volume, TDF and BED. Conclusion : This investigation has revealed a significant correlation between the dose calculated at the rectal dose by ICRU 38(DR) or the most anterior rectal dose by contrast(R) dose to the whole pelvis and the incidence of grade 2, 3 late rectal complications in patients with stage IIB cervical cancer undergoing external beam radiotherapy and HOR ICR. Thus these rectal reference points doses and whole pelvis dose appear to be useful Prognostic indicators of late rectal complication in high dose rate ICR treatment in cervical carcinoma.

• Journal of Technologic Dentistry
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• v.3 no.1
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• pp.9-16
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• 1981

A comparative study was conducted to evaluate the relationship of investing medium to the amount of vertical occlusal changes and to the differences of surface smoothness during denture construction. Three groups of 20 dentures, 30 sets of upper and lower were fabricated of conventional heatcuring acrylic denture base resin, using silicone-gypsum molding techniques, with or without covering the occlusal surfaces of the teeth by artificial stone and all-gypsum molding techniques. The distance between the two reference points indented by 1/2 round bur on the upper and lower frontal surfaces of each articulator were measured and recorded before processing and again after processing and remounting of each denture on the articulator. The differences between the two recordings indicated the amount of vertical opening during denture processing. The difference of surface smoothness were investigated and determined by 3 observers continual comparing of the two randomly selected dentures with each other, which were seperately selected as pairs from the different two groups of 20. The results obtained were as follows: 1. During resin processing no statistically significant differences of the amount of vertical occlusal changes were detected between any of the two groups of two silicone-gypsum and one allgypsum molding techniques, although the amount of vertical opening was somewhat increased when silicone-gypsum molding technique was used. 2. Surface smoothness of the processed denture was makedly by increased when silicone-gypsum molding technique was used.

• Archives of Plastic Surgery
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• v.41 no.6
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• pp.748-752
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• 2014

Background Gynecomastia is benign enlargement of breast tissue in males and is fairly common. Mastectomy not only helps in improving the shape of anterior chest, but can also improve the location of nipple. Therefore, a principle element of mastectomy design is defining the normal location of nipple based on major anatomical reference points. Here, the nipple location was compared for before and after gynecomastia surgery. In addition, the same was also compared between male patients undergoing gynecomastia surgery and control group of subjects without gynecomastia. Methods We retrospectively analyzed gynecomastia patients who underwent conventional subcutaneous mastectomy. Preoperative and postoperative anatomical landmark distances and chest circumferences were measured and compared to the same anthropometric data from 20 healthy adult male controls. Results Nipple locations were compared among 13 patients and 20 controls. The mean weight of resected breast tissue was 246 g, and overall patient satisfaction grade was 4.3 out of 5. In the patient group, the slopes for the height-distance from the sternal notch to the nipple and chest circumference-distance between the mid-line of the sternum and the nipple were 0.175 and 0.125 postoperatively, respectively. The slopes of the control group were 0.122 and 0.177, respectively; these differences were statistically significant (P<0.05). Conclusions Nipple positions were considerably lower in patients with gynecomastia than in control subjects. Subcutaneous mastectomy was associated with mild elevations, but postoperative locations were still lower compared to controls. Further efforts are needed to improve the location of postoperative nipple-areola complex in patients with gynecomastia.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.5199-5206
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• 2010

In this paper, we investigate the buckling analysis of laminated composite plates, using a improved assumed natural strain shell element. In order to overcome membrane and shear locking phenomena, the assumed natural strain method is used. The eigenvalues of the laminated composite plates are calculated by varying the width-thickness ratio and angle of fiber. To improve an shell element for buckling analysis, the new combination of sampling points for assumed natural strain method was applied and the refined first-order shear deformation theory which allows the shear deformation without shear correction factor. In order to validate the present solutions, the reference solutions are used and discussed. The results of laminated composite plates under the in-plane shear loading may be the benchmark test for the buckling analysis.