• The korean journal of orthodontics
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• v.28 no.6 s.71
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• pp.893-904
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• 1998

There are varieties of severe malocclusions, which can be treated orthodontically, but with a great deal of effort. Anterior openbite, in particular, is one malocclusion thought to be more difficult to treat, and therefore, most of them have to be corrected by means of surgical intervention. To solve these problems, numerous studies pertinent to treatment modalities have been introduced with controversies on the effectiveness of treatment. Suggested treatment modalities for anterior openbite are based directly or indirectly on the neuromuscular and morphological features and on the etiologic and/or the environmental factors. Even though the vertical relationship of the face is increased due to the growth variation, the normal occlusal relationship can be achieved by the adequate dentoalveolar compensatory mechanism, but in the case of inadequate or negative dentoalveolar compensation, openbite is likely to be present. If the skeletal dysplasia is too severe to be solved by orthodontic treatment alone, combined treatment with surgery should be done to restore the function and the esthetics of the orofacial complex. In many cases, however, orthodontic alteration of the dentition pertinent to the given skeletal pattern with the proper diagnosis and treatment planning can bring satisfactory results. The treatment changes with the Multiloop Edgewise Archwire(MEAW) therapy occurred mainly in the dentoalveolar region and showed a considerable similarity to the natural dentoalveolar compensatory mechanism. In other words, the MEAW technique allows orthodontists to produce the natural dentoalveolar compensation orthodontically. Even if an openbite is corrected by the orthodontic dentoalveolar compensation suitable for the skeletal pattern, relapse may still occur by the persisting etiologic factors which originally prohibited the natural dentoalveolar compensation. The etiologic factors should be determined at the time of initial diagnosis and should be controlled during treatment and retention.

• Journal of Korea Multimedia Society
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• v.9 no.11
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• pp.1483-1495
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• 2006

The navigation mesh represents a terrain as a set of triangles on which characters may move around. The navigation mesh cab be generated automatically, and it is more flexible in representing 3D surface. The number of triangles to represent a terrain may vary according to the structure of the terrain. As characters are moving around on a navigation mesh, the path planning can be performed more easily by projecting the 3D surfaces into 2D space. However, when the terrain is represented with an elaborated mesh of large number of triangles to achieve more realistic movements, the path finding can be very inefficient because there are too many states(triangles) to be searched. In this paper, we propose an efficient method of path finding in 3D games where the terrain is represented by navigation meshes. Our method uses the visibility tests. When the graph-based search is applied to elaborated polygonal meshes for detailed terrain representation, the path finding can be very inefficient because there are too many states(polygons) to be searched. In our method, we reduce the search space by using visibility tests so that the search can be fast even on the detailed terrain with large number of polygons. First we find the visible vertices of the obstacles, and define the heuristic function as the distance to the goal through those vertices. By doing that, the number of states that the graph-based search visits can be substantially reduced compared to the plane search with straight-line distance heuristic.

• Progress in Medical Physics
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• v.18 no.2
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• pp.93-97
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• 2007

This study was designed to evaluate radiosurgery technique using multiple noncoplanar arc therapy with intensity modulated fine MLC shaped photon beam. The stereotactic radiosurgery was performed with 6-MV X-ray beams from a Clinac 21EX LINAC (Varian, Palo Alto, CA, USA) with a MLC-120, which features a full $40{\times}40cm$ field and is the first MLC for general use that offers 0.5 cm resolution for high precision treatment of small and irregular fields. We used a single isocenter and five gantry-couch combinations with a set of intensity modulated arc therapy. We investigated dosimetric characteristics of 2 cm sized spherical target volume with film (X-OMAT V2 film, Kodak Inc, Rochester NY, USA) dosimetry within $25{\times}25cm$ acrylic phantom. A simulated single isocentric treatment using inversely Planned 3D radiotherapy planning system demonstrated the ability to conform the dose distribution to an spherical target volume. The 80% dose level was adequate to encompass the target volume in frontal, sagittal, and transverse planes, and the region between the 40% and 80% isodose lines was $4.0{\sim}4.5mm$ and comparable to the dose distribution of the Boston Arcs. We expect that our radiosurgery technique could be a treatment option for irregular-shaped large intracranial target.

• Journal of Korean Foot and Ankle Society
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• v.15 no.2
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• pp.51-57
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• 2011

Pilon fractures involving distal tibia remain one of the most difficult therapeutic challenges that confront the orthopedic surgeons because of associated soft tissue injury is common. To introduce and describe the diagnosis, current treatment, results and complications of the pilon fractures. In initial assessment, the correct evaluation of the fracture type through radiographic checkup and examination of the soft tissue envelope is needed to decide appropriate treatment planning of pilon fractures. Even though Ruedi and Allgower reported 74% good and excellent results with primary open reduction and internal fixation, recently the second staged treatment of pilon fractures is preferred to orthopedic traumatologist because of the soft tissue problem is common after primary open reduction and internal fixation. The components of the first stage are focused primarily on stabilization of the soft tissue envelope. If fibula is fractured, fibular open reduction and internal fixation is integral part of initial management for reducing the majority of tibial deformities. Ankle-spanning temporary external fixator is used to restore limb alignment and displaced intraarticular fragments through ligamentotaxis and distraction. And the second stage, definitive open reduction and internal fixation of the tibial component, is undertaken when the soft tissue injury has resolved and no infection sign is seen on pin site of external fixator. The goals of definitive internal fixation should include absolute stability and interfragmentary compression of reduced articular segments, stable fixation of the articular segment to the tibial diaphysis, and restoration of coronal, transverse, and sagittal plane alignments. The location, rigidity, and kinds of the implants are based on each individual fractures. The conventional plate fixation has more advantages in anatomical reduction of intraarticular fractures than locking compression plate. But it has more complications as infection, delayed union and nonunion. The locking compression plate fixation provides greater stability and lesser wound problem than conventional implants. But the locking compression plate remains poorly defined for intraarticular fractures of the distal tibia. Active, active assisted, passive range of motion of the ankle is recommended when postoperative rehabilitation is started. Splinting with the foot in neutral is continued until suture is removed at the 2~3 weeks and weight bearing is delayed for approximately 12 weeks. The recognition of the soft tissue injury has evolved as a critical component of the management of pilon fractures. At this point, the second staged treatment of pilon fractures is good treatment option because of it is designed to promote recovery of the soft tissue envelope in first stage operation and get a good result in definitive reduction and stabilization of the articular surface and axial alignment in second stage operation.

• Tunnel and Underground Space
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• v.22 no.6
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• pp.412-428
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• 2012

To achieve mine development, a large amount of data concerned with the geological structure and the ore body had to be investigated and collected through geological survey, drilling and geophysical explorations. In most previous cases, however, the data were usually analyzed two dimensionally and those results showed some limits because of their 2D presentation. Those 2D maps such as geological plane sections or longitudinal sections cause lots of difficulties in understanding the complex geological structure or the feature of ore body in a spatial way. In this study, research area was set on the abandoned Yangyang iron mine in Korea and the Sugaeng ore body within the mine was selected as the research target to design a mine haulage system for reopening. A 3D mine model of this area was tried to be constructed using a 3D modelling software, GEMS. An accurate 3D model including the ore body, the geological structure, the old underground mine drifts and the new mine drifts was constructed under the purpose of reopening of the abandoned iron mine. Especially, mine design for trackless haulage system was conducted. New inclines and drifts were planned and modelled 3 dimensionally considering the utilization of old drifts and shaft. In addition to the 3D modelling, geostatistical technique was adopted to generate a spatial distribution of the ore grade and the rock physical properties. 3D model would be able to contribute in solving problems such as evaluating ore reserves, planning the mine development and additional explorations and changing the development plans, etc.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.3
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• pp.39-50
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• 2015

This research selected Daegu Metropolitan City representing a combination of natural space and urban space for this case study. To achieve this, a prerequisite was to set up an optimal block size to evaluate landscape diversity of the research site by using a RPR-Area Curve. Further, landscape diversity evaluation was conducted based on land cover map by using FRAGSTATS to analyze spatio-temporal changes. Notably, this research regarded it as the most significant to set forth criteria in order to apply landscape diversity to the development plans of the newtown and outskirt of a city under high pressure development. Results derived from this research are summarized as follows. According to the results derived from establishing the optimal block size, a size about $2km^2$ was analyzed to measure landscape diversity of the research site. Also, according to the results derived from land diversity evaluation based on land cover map, land diversity was highly measured around urban stream such as Nakdong River and Geumho River, and in particular, the value of landscape diversity was measured considerably high around the urban parks. Results derived from analysis on spatio-temporal changes of land diversity demonstrated that a certain level of urban development exerted a positive effect on an increase in land diversity, but consistent urban development lowered a value of landscape diversity. Results derived from regression analysis to set forth the optimal urban space showed that an urban area of a space about $2km^2$ exerted a positive effect at a rate of about 0~43.3% and a negative effect at a rate about 43.3~100%. In conclusion, the results of this research are considered to provide important basic data for future urban and landscape planning. Nonetheless, as only the layout on the 2D plane was analyzed in this research, further research in future is required to complexly consider diverse factors such as height of structure and change in visible real area arising from geographical features.

• Journal of Periodontal and Implant Science
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• v.36 no.1
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• pp.147-154
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• 2006

Surgical intervention in the posterior maxillary region requires detailed knowledge of maxillary sinus anatomy and the possible anatomical variations. This study evaluated the incidence, location of maxillary sinus septa by using radiographic (panoramic radiography and computed tomography) findings and comparison of panoramic radography with CT in antral anatomical variation. This study was based on data from 70 sinuses in partial dentate maxilla. The sample consisted of 61 patients(25 women and 36 men, with ages ranging between 19 and 77 years and a mean age of $49.4{\pm}11.3$ years) who were being treatment-planned to receive implant-supported restorations. First, the panoramic images were examined for the presence of antral septa by radiologist and examiner who don't know about CT findings. And incidence of antral septa was evaluated using an axial plane of CT image. The incidence of septa was compared between panoramic radiography and CT. The accuracy of the incidence was compared between radiologists and dentists. A total of 20 septa were found in 70 sinuses on CT image and the prevalence of one or more septa per sinus was found to be 28.6%. The assumed incidence of septa on panoramic radiography was $27.6%{\pm}2.2%$ in radiologist and $31.9%{\pm}5.8%$ in dentists. Erroneous diagnosis rate was 11.42% in radiologist and 15.96% in dentists. 40% of antral septa were located in the anterior(premolar) region, 30% of septa were located in the middle(first molar) and posterior(second molar) region separately. Prior to implant placement, it seems appropriate to consider panoramic radiography as a standard radiographic examination and periapical radiographs may be used to complete the findings in regions not sharply depicted in the panoramic radiograph. And cross-sectional imaging should be used in sites with severe bone loss and close proximity of the maxillary sinus.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.1
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• pp.42.1-42.1
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• 2011

The main payload of the Science and Technology Satellite 3 (STSAT-3), Multipurpose Infrared Imaging System (MIRIS), will be equipped with the wide-field near-infrared camera. Its wide field-of-view ($3.67^{\circ}{\times}3.67^{\circ}$) is optimal for the observation of the zodiacal light (ZL), the sunlight scattered by the interplanetary dust (IPD). The MIRIS will continuously monitor the seasonal variation of the ZL towards both north and south ecliptic poles, which is caused by the asymmetries of the IPD distribution with respect to the Sun and the ecliptic plane. In addition to the monitoring observations, we are planning pointed observations for compelling structures in the ZL, the asteroidal dust bands and the gegenschein. This presentation proposes the zodiacal light observations with the MIRIS and discusses the expected results.

• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.2935-2940
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• 2023

A polystyrene phantom was developed following the guidance of the International Atomic Energy Association (IAEA) for gamma knife (GK) quality assurance. Its performance was assessed by measuring the absorbed dose rate to water and dose distributions. The phantom was made of polystyrene, which has an electron density (1.0156) similar to that of water. The phantom included one outer phantom and four inner phantoms. Two inner phantoms held PTW T31010 and Exradin A16 ion chambers. One inner phantom held a film in the XY plane of the Leksell coordinate system, and another inner phantom held a film in the YZ or ZX planes. The absorbed dose rate to water and beam profiles of the machine-specific reference (msr) field, namely, the 16 mm collimator field of a GK Perfexion^TM or Icon^TM, were measured at seven GK sites. The measured results were compared to those of an IAEA-recommended solid water (SW) phantom. The radius of the polystyrene phantom was determined to be 7.88 cm by converting the electron density of the plastic, considering a water depth of 8 g/cm². The absorbed dose rates to water measured in both phantoms differed from the treatment planning program by less than 1.1%. Before msr correction, the PTW T31010 dose rates (PTW Freiberg GmbH, New York, NY, USA) in the polystyrene phantom were 0.70 (0.29)% higher on average than those in the SW phantom. The Exradin A16 (Standard Imaging, Middleton, WI, USA) dose rates were 0.76 (0.32)% higher in the polystyrene phantom. After msr correction factors were applied, there were no statistically significant differences in the A16 dose rates measured in the two phantoms; however, the T31010 dose rates were 0.72 (0.29)% higher in the polystyrene phantom. When the full widths at half maximum and penumbras of the msr field were compared, no significant differences between the two phantoms were observed, except for the penumbra in the Y-axis. However, the difference in the penumbra was smaller than variations among different sites. A polystyrene phantom developed for gamma knife dosimetry showed dosimetric performance comparable to that of a commercial SW phantom. In addition to its cost effectiveness, the polystyrene phantom removes air space around the detector. Additional simulations of the msr correction factors of the polystyrene phantom should be performed.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.4
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• pp.293-307
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• 2023

Jaw motion tracking, which is introduced in recent case reports, is a method which records the patient's individualized pathway of the mandibular movements along with facebow transfer, and reproduces the information in the virtual space of computer-aided-design/computer-aided-manufacturing (CAD-CAM) software. In this present case, a collapse of the occlusal plane was observed, due the loss of posterior teeth for a long period. Full-mouth rehabilitation with an increase in the occlusal vertical dimension was planned. First, the patient's mandibular movements were recorded on the newly established jaw relation by jaw tracking, and this information was assembled with the patient's intraoral data to create a virtual patient. Implant planning and diagnostic wax-up was done on the virtual patient, leading the fabrication of the provisional prosthesis. On the newly established jaw relation with an increase in the occlusal vertical dimension, canine guidance of the provisional prosthesis was checked. Finally, the provisional prosthesis was carried out to the definitive prosthesis. Using the advantages of the technologies in the digital dentistry, the patient was satisfied with the function and the esthetics after the treatment.