• Journal of the Institute of Convergence Signal Processing
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• v.22 no.3
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• pp.122-127
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• 2021

Flow features near the ship bow such as wave breaking, small scale phenomena have been studied using numerical methods. In this study, the bow shaped wedge was adopted which is from previous paper [1, 2] and the conditions of simulation were Re = 1.64 × 10⁵) and Fr = 2.93. Star CCM+, one of the commercial CFD programs has been used for the simulations. Simulation results such as wave profiles near the ship bow, shape of plunging jet, air entrainment, and wave breaking process have been compared with previous experimental and numerical studies. Overall results showed good agreements with previous studies. Profiles of bow waves showed that overturning jet has been created and broken along the wedge. Plunging wave breaking has been observed along the wedge and four components of plunging wave breaking process were shown. It is confirmed that velocity near the overturing jet significantly increased during plunging wave breaking.

• The korean journal of orthodontics
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• v.31 no.3 s.86
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• pp.311-323
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• 2001

One of the various mechanics used to treat unilateral Class II malocclusion is head gear with asymmetric face bow. We made the finite element models of unilateral Class II maxillary dental arch and power arm asymmetric face bow. We designed this experiment to observe stress distribution of periodontal ligament, reaction force, and displacement and to understand force system, so to predict the therapeutic effect. On the basis of computerized tomograph of maxillary dental arch of 25 years old male with normal occlusion without extraction and orthodontic treatment history, we made finite element models of maxillary dental arch and periodontal ligament. Then we modified that model to unilateral maxillary Class II malocclusion model of which maxillary left molar displaced mesially. Also, We made finite element model of asymmetric face bow of which right outer bow shorter than left by 25mm(RMO, Penta-FormTM/Medium size, 0.045 inch iner bow, 0.072 inch outer bow). After that, retraction force of 250g, 300b, 350g were applied to maxillary first molar. We concluded as follow. 1. The Net force that both maxillary first molars were received increased as the retraction force increased. Mesially positioned tooth received more force than normally positioned tooth. But, both tooth were received distal force, so distal movement occured. 2. Both tooth received buccal lateral force. In analysis of force element, as the retraction force were increased, force of X-axis at mesially positioned tooth decreased, and force of X-axis at normally positioned tooth increased. so lateral force component moved to the side received less force from more force. 3. There were rotation, tipping with distal movement in maxillary first molar. As retraction force were increased, rotation and tipping also increased. More tipping and rotation occured at the side received more force, that is, mesially positioned tooth. Though it Is small change, displacement of same pattern occur in normally positioned tooth

• The Journal of Advanced Prosthodontics
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• v.15 no.5
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• pp.271-280
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• 2023

PURPOSE. This in vitro study aimed to compare the accuracy of the conventional facebow system and the newly developed POP (PNUD (Pusan National University Dental School) Occlusal Plane) bow system for occlusal plane transfer in asymmetric ear position. MATERIALS AND METHODS. Two dentists participated in this study, one was categorized as Experimenter 1 and the other as Experimenter 2 based on their clinical experience with the facebow (1F, 2F) and POP bow (1P, 2P) systems. The vertical height difference between the two ears of the phantom model was set to 3 mm. Experimenter 1 and Experimenter 2 performed the facebow and POP bow systems on the phantom model 10 times each, and the transfer accuracy was analyzed. The accuracy was evaluated by measuring the angle between the reference virtual plane (RVP) of the phantom model and the experimental virtual plane (EVP) of the upper mounting plate through digital superimposition. All data were statistically analyzed using a paired t-test (P < .05). RESULTS. Regardless of clinical experience, the POP bow system (0.53° ± 0.30 (1P) and 0.19° ± 0.18 (2P) for Experimenter 1 and 2, respectively) was significantly more accurate than the facebow system (1.88° ± 0.50 (1F) and 1.34° ± 0.25 (2F), respectively) in the frontal view (P < .05). In the sagittal view, no significant differences were found between the POP bow system (0.92° ± 0.50 (1P) and 0.73° ± 0.42 (2P) for Experimenter 1 and 2, respectively) and the facebow system (0.82° ± 0.49 (1F) and 0.60° ± 0.39 (2F), respectively), regardless of clinical experience (P > .05). CONCLUSION. In cases of asymmetric ear position, the POP bow system may transfer occlusal plane information more accurately than the facebow system in the frontal view, regardless of clinical experience.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.817-818
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• 2012

• The korean journal of orthodontics
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• v.37 no.5
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• pp.331-340
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• 2007

The aim of this study was to determine firstly the characteristics of esthetic lips in Korean females and secondly to measure the changes of the lips before and after anterior segmental osteotomy in bimaxillary protruded patients. Methods: Samples consisted of 30 models and 26 nonmodels, and 10 patients who had received anterior segmental osteotomy. Twelve linear measurements, 5 angular measurements, and the lip perimeter and area were measured. These results were compared for each group using unpaired and paired t-tests. Results: Full face width, nose to chin, upper vermilion height and angle, lateral heights at the point of the tips of Cupid's bow, central bow angle, and the lower lip to chin lengths were significantly greater in nonmodels than in models. However, overall lip width, lower vermilion height and angle, tip-to-tip of Cupid's bow lip perimeter, and lower vermilion area were greater in models than in nonmodels. Comparison of before and after anterior segmental osteotomy revealed that the values for the upper vermilion and lateral heights, the angle to Cupid's bow tip lengths, and upper vermilion area of post-operative patients had become similar to those of Korean female models. Our findings demonstrated that Korean female models have a fuller lower vermilion & thinner upper vermilion compared with nonmodel controls, as determined by the vermilion heights, angles, and areas. Conclusions: It will be helpful for clinicians to use these measurements as guidelines for improving patients' facial esthetics.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.4
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• pp.694-699
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• 2001

The prognosis for class III patients in growing child can be made in mixed dentition and the severity of the symptom is often amenable to early intervention. Class III malocclusion can be classified as functional class lit and skeletal origin. Skeletal Class III malocclusion is usually characterized by overdeveloped mandible, underdeveloped maxilla, but the cause of pseudo class III is most dentoalveolar or functional shift of mandible. The primary goal of early intervention of malocclusion is to supply an environment that is conducive to the development of favorable occlusal relationships and avoiding of worsening of the problems. Inverted labial bow appliance is introduced as an appliance to combine the advantage of active plate and activator. It is undemanding with this appliance to initiate not only dentoalveolar expansion of upper dentition but also to orient the functional retrusion of mandible. With simple design the compliance for patients such as mouth breathing problem can be improved. For successful use of this appliance it is utmost important to make accurate and early diagnosis between pseudo- and skeletal class III malocclusion. This article will demonstrate the use of an Inverted labial bow appliance for early treatment of a functional Class III malocclusion. After 4 month treatment, anterior crossbite was treated and the results were achieved mainly dentoalveolar change of upper and lower anterior teeth.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.1
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• pp.44-54
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• 2023

In order to manufacture functional and esthetic prostheses, it is essential to accurately transmit information about the patient's occlusal plane. In particular, in the case of a completely edentulous patient, the occlusal plane is very important to correctly support the soft tissue, to achieve aesthetic harmony with the facial appearance, and to properly pronounce it, and to form a balanced occlusal relationship for stable mastication. In the conventional method, various facebow systems were used to transmit patient's information from the clinic to the laboratory, but there were several limitations in the process of transferring them to CAD. To simplify this process, a prefabricated POP (PNUD Occlusal Plane) Bow system was recently developed. In this case, a CAD-CAM (Computer-aided design-computer-aided manufacturing) treatment dentures reflecting the patient's occlusal plane information was manufactured using the POP Bow system during the treatment of a completely edentulous patient, and aesthetic and functional satisfaction was obtained.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.309-313
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• 2004

Prediction of green water loads acting an the bow deck is an essential part for the design of bow structures against the green water impact. Proper technique of the green water simulation is highly required for the prediction of green water loads. In this paper, a new numerical method for green water simulation, which is based an predictor-corrector-upwind finite difference scheme of the 2nd kind, is introduced. Through the comparisons between computed' results and experimental measurements, it is verified that the present numerical tool is adequate as a practical calculation tool for the green water problem.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.497-500
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• 2000

There are many researches to increase bandwidth of the microstrip patch antenna for wireless LAN. In spite of broad bandwidth, Bow-Tie microstrip patch antenna, broadband microstrip patch antenna, has disadvantages that are low gain and big size. In this paper, stacked Bow-Tie microstrip patch antenna for wireless LAN is designed in 5.725∼5.825㎓ band. This antenna has characteristics that are broadband bandwidth, high gain and small size compared with microstrip patch antenna. In simulated results, the return loss is -34.2㏈ at 5.78㎓ and bandwidth is 11.345% for VSWR 2：1 and 7.75% for VSWR 1.5：1. In measured results, the return loss is -38.45㏈ at 5.78㎓ and bandwidth is 13% for VSWR 2：1 and 5.6% for VSWR 1.5：1. It has 59.37$^{\circ}$-3㏈ beam width and 6.5㏈ gain.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.8
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• pp.1352-1358
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• 2006

In this paper, we have fabricated and tested a broad band bow-tie slot antenna with dual reflector. If we put 1/2 length thin and long slot on a wide metal plate, the slot antenna radiates efficient and strong radio wave as same as 1/2 dipole antenna does. we made with bow-tie form slot which has wider broad band than normal rectangular slot. At first, we made and test a single reflector slot antenna. To enlarge the broad band, we inserted another reflection plate between the slot antenna and reflection plate. After the test, we could have known that the low band(VSWR<2.0) has about $22%(793MHz\sim992MHz)$, high band(VSWR<2.0) has about 61% (1626MHz\sim3064MHz).