• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.20 no.2
• /
• pp.163-167
• /
• 1990

The author has evaluated the panoramic image of the mandibular condyle according to its horizontal condylar angle (0˚, 10˚, 20°, 30°, 40°) and mandibular position (standard, 25㎜ forward and reverse position). The results were as follows: 1. The larger the horizontal condylar angle was, the larger the horizontal magnification was in all positions. 2. In case of small horizontal condylar angle, profile view could be obtained in 25㎜ forward and reverse position. 3. In case of large horizontal condylar angle, profile view could not be obtained in any positions.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2003.05a
• /
• pp.160-163
• /
• 2003

For the purpose of rolling hard metals such as silicon steel and non-ferrous metals, the backup roll driven-type mill has been widely used in cold rolling industry. Since the backup roll drive results in horizontal bending of the work rolls and therefore exerted reciprocal action on the roll gap contour, the selection of slim work rolls is very restricted. In this paper, we present an analytic equation based scheme to determine a proper horizontal position of work roll minimizing the horizontal force subject to mechanical constraints.

• Journal of Oral Medicine and Pain
• /
• v.21 no.1
• /
• pp.55-65
• /
• 1996

This study was performed to investigate the effects of head posture and occlusal splint on the vertical dimension in mandibular rest position and swallowing. Thirty health dental students ware selected lot this study and BioEGNⓡ(Bioresearch Inc., USA) was used for measuring interocclusal distance during rest - swallowing - rest - tapping movement. This swallowing movements were observed in both normal head posture(NHP) and forward head posture (FHP). Thickness of occlusal splint was about 2mm at posterior molar area and even tooth contact were achieved on light biting. The four mandibular positions at which interocclusal distance measured were swallowing position, after swallowing position in which interocclusal distance was maximum, rest position follows swallowing, and tapping position after rest. Changes of distance in each position were measured for three mandibular planes, that is, sagittal, frontal, and horizontal plane, respectively. The results obtained were as follows : 1. In normal head posture, the mandible was raised 1.03mm without splint, and 0.77mm with splint on swallowing, and there was no significant difference between the two. In horizontal plane, however, mandible was displaced more anteriorly in both swallowing position and tapping position with splint. 2. In forward head posture, the mandible was less raised with splint on swallowing, but features in horizontal plane were almost same as those in normal head posture. 3. In natural dentition, significant difference between NHP and FHP were observed in horizontal plane trajectory for swallowing and tapping position. But the difference for same positions were observed in frontal trajectory with splint. 4. Total amount of mandibular movement of two groups classified with sagittal interocclusal distance of swallowing position generally showed significant difference between the higher and the lower height group in head posture without splint. 5. Correlationship among total amount of mandibular movement for three mandibular planes were observed between sagittal plane and horizontal plane, and between sagittal plane and frontal plane in head posture without splint.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2022.04a
• /
• pp.235-236
• /
• 2022

In the present study, the effect of horizontal vent position on fire phenomena in the enclosure with vertical and horizontal vents was examined using numerical simulation. Case 1 indicates the condition that the horizontal vent is in the center of the ceiling. Case 3 indicates the condition that the horizontal vent is far away from the vertical vent. Case 2 indicates the condition that the horizontal vent is installed between Case 1 and Case 3. The temperature distribution, smoke layer temperature, velocity distribution, and mass flow rate of horizontal vent flow were analyzed. In Case 2, the temperatures were lowest and the mass flow rate through the horizontal vent was largest. This is because the flame is inclined by the inflow through the vertical vent. Hence, to determine the proper horizontal vent location for the high smoke ventilation performance, the inflow through the vertical vent and its effect on flame behavior should be considered.

• The Journal of Advanced Prosthodontics
• /
• v.10 no.6
• /
• pp.401-407
• /
• 2018

PURPOSE. When performing an occlusal procedure, it is recommended that the patient should be sitting straight with the head in a natural position. An inappropriate mandibular position caused by an incorrect occlusal record registration or occlusal adjustment can result in damaged teeth and cause functional disorders in muscles and temporomandibular joints. The purpose of this study was to clarify the influence of horizontal cephalic rotation on mandibular position by investigating the three-dimensional positions of condylar and incisal points. MATERIALS AND METHODS. A three-dimensional jaw movement measurement device with six degrees of freedom (the WinJaw System) was used to measure condylar and incisal points. The subjects were asked to sit straight with the head in a natural position. The subjects were then instructed to rotate their head horizontally $0^{\circ}$, $10^{\circ}$, $20^{\circ}$, $30^{\circ}$, $40^{\circ}$, $50^{\circ}$and $60^{\circ}$ in the right or left direction. RESULTS. The results indicated that horizontal cephalic rotation made the condyle on the rotating side shift forward, downward, and toward the inside, and the condyle on the counter rotating side shift backward, upward, and toward the outside. Significant differences in deviations were found for angles of rotation higher than $20^{\circ}$. The incisal point shifted in the forward and counterrotating directions, and significant differences were found for angles of rotation higher than $20^{\circ}$. CONCLUSION. The mandibular position was altered by horizontal cephalic rotations of more than $20^{\circ}$. It is essential to consider the possibility of deviation of the mandibular position during occlusal procedures.

• Journal of Space Technology and Applications
• /
• v.3 no.1
• /
• pp.58-71
• /
• 2023

This paper describes a navigation system design for horizontal position estimation using inertial measurement sensors and celestial navigation. In space, stars are widely spread objects in the celestial sphere and have been used mainly to obtain attitude information through star observation. However, it is also possible to obtain information about the horizontal position with the altitude of the star. It is called celestial navigation which is the same principle that former navigators used to locate themselves while sailing on the sea. In particular, in deep space where GPS is not available, it is important to obtain information on the location by making use of stars that are relatively easy to observe. Therefore, we introduce a navigation system that can estimate horizontal position and design two types of systems, loosely coupled and tightly coupled depending on how the measurements are utilized. It is intended to help in the future design of navigation system using celestial navigation by simulation studies that not only verify whether the system correctly estimates horizontal position but also comparing the performance of loosely and tightly coupled methods.

• Journal of Ocean Engineering and Technology
• /
• v.32 no.4
• /
• pp.222-227
• /
• 2018

Most underwater acoustic arrays for low frequency operation are deployed vertically, but a mid-range frequency horizontal array system is being developed by the Korea Research Institute of Ships and Ocean Engineering (KRISO). The horizontal array platform is deployed underwater and kept in place by weather vaning mooring. This is essential because it is nearly impossible to keep a submerged body at a given position in the water without any external force. Hence, the horizontal array platform can maintain the desired position in the presence of a weak tidal current. The objective of this study is to design an underwater platform that can maintain its horizontal position in a weak current. First, the authors investigated various virtual models, selected one of the models, and performed a small model test of the selected model at a basin. We calculated the external forces associated with the 2D motion, and then we conducted a large basin test followed by a circulation water channel test for the manufactured array platform. The results of the simplified 2D motion calculation essentially matched the results of the underwater test.

• The korean journal of orthodontics
• /
• v.27 no.5 s.64
• /
• pp.743-760
• /
• 1997

This study was done to evaluate the correlations between the size, the form of the cranial base, head posture and the horizontal and vertical position of craniofacial structures. For this purpose, 100 cephalometric radiographs were taken from the sample composed of 51 male and 49 female, 12 measurement criteria and 37 reference points were established and digitized, then calculation was performed for the values of measurement variables and the horizontal and vertical position of reference points. The correlations be4ween them were analyzed statistically and mean facial diagrams were constructed and compared with the selected groups which were composed of 10 Samples each as large and small group from the measurement value. The following results were obtained: 1. The angles n-s-ba and n-s-ar as variables for the ion of cranial base correlated highly to the horizontal and vertical position of reference points in the cervical column with statistical significance($0.1\%$ level). 2. The angles n-s-ba and n-s-ar as variables for the form of cranial base correlated to the horizontal position of the reference points in the facial structure with statistical significance($1\%$ level), but not to the vertical position of them($5\%$ level). 3. The length n-s, s-ba, and n-ar as variables for the size of cranial base were correlated th the position of craniofacial structures in various ways, but in general, highly correlated to the horizontal and vertical position of midfacial structures around the teeth and alveolar area. 4. the angle NSL/CVT and NSL/OPT as postural variables tot the inclination of cranial base and cervical column were correlated to the horizontal position of the craniofacial structures with statistical significance($1\%$ level), but not to the vortical position of them($5\%$ level). 5. The angle OPT/HOR and CVT/HOR as postural variables lot the inclination of cranial base and true horizontal line were not correlated to the horizontal and vertical position of the craniofacial structures with statistical significance($5\%$ level). 6. The correlation between the measurement variables and horizontal and vortical positions of the reference poits in soft tissue were shown as similar to the related hard tissue points.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.28 no.1
• /
• pp.7-16
• /
• 1998

The Scanora/sup (R)/ X-ray unit uses the principles of narrow beam radiography and spiral tomography. Starting with a panoramic overview as a scout image. multiple tomographic projections could be selected. This study evaluated the accuracy of spiral tomography in comparison to routine panoramic radiography for dental implant treatment planning. An experimental study was performed on a cadaver mandible to assess the accuracy of panoramic radiography and spiral tomography film images for measurement of metallic spheres. After radiographic images of the metallic spheres on the surgical stent were measured and corrected for a fixed magnification of radiographic images. following results were obtained. 1. In the optimal position of the mandible. the minimal horizontal and vertical distortion was evident in the panoramic radiography images. The mean horizontal and vertical magnification error in anterior sites was 5.25％ and 0.75％. respectively. The mean horizontal and vertical magnification error in posterior sites was 0.50％ and 1.50％. respectively. 2. In the displaced forward or in an eccentric position of the mandible. the magnification error of the panoramic radiography images increased significantly over the optimal position. Overall, the mean horizontal magnification error of the anterior site in the different positions changed dramatically within a range of -17.25％ to 39.00％, compared to the posterior range of -5.25％ to 8.50％. However, the mean vertical magnification error stayed with the range of 0.5％ to 3.75％ for all the mandibular positions. 3. The magnification effects in the tomographic scans were nearly identical for the anterior and posterior with a range of 2.00％ to 5.75％ in the horizontal and 4.50％ to 5.50％ in the vertical dimension, respectively. 4. A statistically significant difference between the anterior and posterior measurements was found in the horizontal measurements of the panoramic radiography images of the displaced forward and backward position of the mandible(P<0.05). Also a significant difference between the optimal panoramic and tomographic projections was found only in the vertical measurement(P<0.05).

• Imaging Science in Dentistry
• /
• v.46 no.2
• /
• pp.77-85
• /
• 2016

Purpose: To analyze the relative position of the mandibular foramina (MnFs) in patients diagnosed with skeletal class III malocclusion. Materials and Methods: Computed tomography (CT) images were collected from 85 patients. The vertical lengths of each anatomic point from the five horizontal planes passing through the MnF were measured at the coronoid process, sigmoid notch, condyle, and the gonion. The distance from the anterior ramus point to the posterior ramus point on the five horizontal planes was designated the anteroposterior horizontal distance of the ramus for each plane. The perpendicular distance from each anterior ramus point to each vertical plane through the MnF was designated the horizontal distance from the anterior ramus to the MnF. The horizontal and vertical positions were examined by regression analysis. Results: Regression analysis showed the heights of the coronoid process, sigmoid notch, and condyle for the five horizontal planes were significantly related to the height of the MnF, with the highest significance associated with the MnF-mandibular plane (coefficients of determination ($R^2$): 0.424, 0.597, and 0.604, respectively). The horizontal anteroposterior length of the ramus and the distance from the anterior ramus point to the MnF were significant by regression analysis. Conclusion: The relative position of the MnF was significantly related to the vertical heights of the sigmoid notch, coronoid process, and condyle as well as to the horizontal anteroposterior length of the ascending ramus. These findings should be clinically useful for patients with skeletal class III mandibular prognathism.