• Korea-Australia Rheology Journal
• /
• v.18 no.4
• /
• pp.217-224
• /
• 2006

Rapid flow advancement without void formation is essential in the liquid composite molding (LCM) such as resin transfer molding (RTM) and vacuum assisted resin transfer molding (VARTM). A highly permeable layer in multi-layered preform has an important role in improvement of the flow advancement. In this study, a multi-layered preform which consists of three layers is employed. Radial flow experiment is carried out for the multi-layered preform. A new analytic model for advancement of flow front is proposed and effective permeability is defined. The effective permeability for the multi-layered preform is obtained analytically and compared with experimental results. Compaction test is performed to determine the exact fiber volume traction of each layer in the multi-layered preform. Transverse permeability employed in modeling is measured experimentally unlike the previous studies. Accurate prediction of flow advancement is of great use for saving the processing time and enhancing product properties of the final part.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 1999.06a
• /
• pp.183-190
• /
• 1999

We have started the field test of the VOD service since April 1996, in Huis Ten Bosch which is one of the famous theme parks in Japan. In three years, total about 100 thousands people have used this VOD system and evaluated it. This test verifies that the VOD system which provides moving picture by MPEG2 via broad bandwidth ATM network has already reached the level of actual use. And also we get the know-how to construct contents, or how to manage network resources and server resources, and we have proposed them.

• Journal of architectural history
• /
• v.15 no.3
• /
• pp.7-25
• /
• 2006

This research examines symbolic meanings of architectural style of Japanese ruling era of Korea through analysis of Expo buildings. Expo buidings of Joseon Product Evaluation Expo(1915), Joseon Expo(1929), and Joseon Grand Expo(1940) are chosen as subjects of this research. Expos held in Korea since 1945 were creatures of colonial reign and their objectives are advertising the advancement of Japan. New and latest architectural styles of Western countries were used as a symbol of advancement in non-western countries. Renaissance style and Secession style in Joseon Product Evaluation Expo and Modernism style in Joseon Expo were introduced as architectural styles that symbolize advancement. On the contrary, the traditional architectural style of Joseon Dynasty was distorted as symbol of backwardness. Latest Western Architectural Styles were used elaborately and Intentionally to symbolize advancement and industrialization by Japanese ruling power and companies. Specially, Modernism style operating as 'symbol of advancement' is characteristic of non-western society in attempt to proceed Modernization through Westernization. Also, it can be suggested that architectures in Modernism style are used in ways to symbolize the advancement of the colonial reign authorities within the colonial society.

• Proceedings of the IEEK Conference
• /
• 2002.07b
• /
• pp.822-825
• /
• 2002

Geographic Information System(GIS) has become an essential tool for making efficient interaction with both natural and artificial envirionment. Currently, it is being used on an inteligent tool in many device like the personal digital assistant(PDA) and the cellular phone and so on. However, these devices show very low performance comparing to a personal computer(PC). These devices(PDA, celluar phone) posses a less powered device profile. The less powerful hardware make these devices in capable to handle GIS based large spacial data. In this paper, we propose a new concept of multi-tier GIS oriented architecture to improve the data transfer performance providing only the necessary information required by the user using semantic filter.

• The korean journal of orthodontics
• /
• v.49 no.4
• /
• pp.265-276
• /
• 2019

Patients with obstructive sleep apnea (OSA) whose phenotype belongs to a craniofacial vulnerability are referred from sleep doctors to orthodontists. In adults, for osseo-pharyngeal reconstruction (OPR) treatment, permanent maxillomandibular advancement (MMA) surgery and use of a temporary mandibular advancement device (MAD) are applied. This case report demonstrates successful treatment of OSA through application of phased MAD and MMA in a 16-year-old male with craniofacial deformity and residual growth potential. This patient showed skeletal and dentoalveolar changes after 7-year MAD use throughout post-adolescence, which affected the design and timing of subsequent MMA surgery, as well as post-surgical orthodontic strategy. This case report suggests that OPR treatment can be useful for treatment of OSA in post-adolescent patients, from an orthodontic point of view, in close collaboration with sleep doctors for interdisciplinary diagnosis and treatment.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.43 no.3
• /
• pp.152-159
• /
• 2017

Objectives: The aim of this study was to investigate the effects of advancement magnitude and changes in mandibular plane angle on the stability of mandibular advancement. Materials and Methods: This retrospective cohort study evaluated the postoperative stability of mandibular advancement in class II skeletal subjects who underwent bilateral sagittal split osteotomy. Radiographs taken preoperatively, immediately postoperatively and 1 year postoperatively were traced and analyzed using linear and angular measurements. To determine horizontal and vertical relapse, an X-Y coordinate system was established in which the X-axis was constructed by rotating S-N downward by $7^{\circ}$ (approximation of the Frankfort horizontal plane) and the Y-axis was defined as a line perpendicular to the X-axis and passing through the point Sella. For certain reference points including point A, point B, pogonion and menton, the perpendicular distance between each point and both axes was determined and cephalometric variables were recorded as X and Y coordinates. Results: Twenty-five subjects were studied. A significant correlation between the amount of mandibular advancement and relapse in the B point (vertical and horizontal) and the pogonion point was observed (vertical and horizontal, P<0.001). Evaluation of data demonstrated a positive correlation between the mandibular plane angle (SN/ML) change and vertical relapse in the B point (P<0.05). A simple regression model demonstrated that 74% of horizontal relapse and 42.3% of vertical relapse in the B point was related to the amount of mandibular advancement. The receiver operating characteristic test showed that 8.5 mm mandibular advancement is related to a relapse rate of 1 mm or more in the pogonion, vertically or horizontally. Conclusion: The magnitude of mandibular advancement is a stronger surgical predictor for horizontal rather than vertical relapse at the B point. Changes in mandibular plane angle (SN/ML) during surgery affect vertical, but not horizontal relapse at the B point.

• The korean journal of orthodontics
• /
• v.40 no.2
• /
• pp.115-126
• /
• 2010

This case report describes the treatment of a 66 year old adult patient with a diagnosis of severe obstructive sleep apnea who was intolerant of nasal continuous positive airway pressure (nCPAP) treatment and oral appliance therapy. An alternative treatment of snoring and obstructive sleep apnea (OSA) with 2 orthodontic microimplants anchored to the mandible providing skeletal anchorage for mandibular advancement was implemented. After a 2 week healing period, a custom designed facemask provided extraoral anchorage to which the microimplants were connected to for titratable mandibular advancement. Microimplant Mandibular Advancement (MiMA) therapy resulted in resolution of the symptoms of severe OSA with a reduction of the apnea-hypopnea index (AHI), snoring and OSA symptoms.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.36 no.2
• /
• pp.94-99
• /
• 2010

The purpose of this study was to examine the soft tissue changes in skeletal class II patients after mandibular advancement by bilateral sagittal split ramus osteotomy (BSSRO). In Asian population, the incidence of skeletal class II malocclusion is lower than that of skeletal class III malocclusion unlike the caucasians. This study was conducted to figure out the ratio at which hard tissue and soft tissue changes after mandibular advancement by analyzing cephalograms of 13 patients that have undergone the mandibular advancement surgery. As a result, change ratios of Li, B', Pog' according to the movement of li, B, Pog were found to be 0.59, 1.06, 0.82. Also, vertical height of vermilion zone (Si-Vb) and lower lip and chin (Si-Me') were measured to evaluate vertical changes. Vermilion zone showed tendency to decrease by 1.02 mm on the average postoperatively, whereas vertical length of lower lip and chin showed tendency to increase by 3.57 mm on the average.

• Journal of Oral Medicine and Pain
• /
• v.39 no.2
• /
• pp.35-45
• /
• 2014

Many therapeutic modalities including continuous positive airway pressure, surgery, and oral appliances are used to treat patients with sleep-disordered breathing. However, there are no definitive treatment modalities for individual patients due to various causes of sleep-disordered breathing. Clinicians should have select best options for individual patients and it is quite challenging process. Oral appliances attracted clinical attention for its convenience and safety. Several designs of oral appliances are introduces such as soft palate lifter, tongue retaining device, and various appliances which aimed to mandibular advancement. Among these oral appliances, mandibular advancement devices (MADs) are considered the most excellent based on their effectiveness and patient tolerance. Although MADs are not guarantee dramatic outcome and less consistent than continuous positive airway pressure, they offer several advantages over continuous positive airway pressure and surgical methods, including non-invasiveness, silence, portability, and tolerability, simplicity. Therefore, general dental practitioner who had passed sleep dental curriculum or coursework can treat the patients with sleep problems. This article reviews the history, clinical indications, suggested mechanism of actions, various positive effects and several side effects, factors predicting a favorable outcome, determining amounts of mandibular advancement, compliance and long-term efficacy of MADs use.

• Archives of Craniofacial Surgery
• /
• v.19 no.1
• /
• pp.64-67
• /
• 2018

Varying degrees of complications can occur after hyaluronic acid filler injections. Tissue necrosis due to interruption of the vascular supply is an early complication that can be severe. If the site of tissue necrosis due to the filler injection is the forehead, successfully reconstructing the region without distorting the key landmarks is challenging. We describe the case of a 50-year-old man who experienced widespread forehead skin necrosis after hyaluronic acid filler injection in the glabellar area. We successfully covered the forehead area with a $3{\times}4-cm^2$ midline necrotic tissue using the modified double-opposing rotation-advancement flap method. Although modified double-opposing rotation-advancement flap closure has the disadvantage of leaving a longer scar compared to conventional double-opposing rotation-advancement flap closure, the additional incision line made along the superior border of the eyebrow aids in camouflaging the scar and decreases eyebrow distortion. Therefore, it is believed that the modified double-opposing rotation-advancement flap technique is an excellent tool for providing adequate soft tissue coverage and minimal free margin distortion when reconstructing widespread skin necrosis in the central mid-lower forehead that can occur after filler injection in the glabellar area.