• Journal of KIISE:Software and Applications
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• v.33 no.2
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• pp.220-230
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• 2006

As the computing technique and mobile devices get developed, the demand of multimedia contents for mobile environment has been increased. The multimedia contents provided on PDA has so far been limited to the materials such as video and audio. MPEG-4 is the international standard used for supporting to properly save, communicate multimedia in formation such as video, audio, image, text and two-dimensional object, which can present various, multimedia contents by using adaptation techniques. However, since most MPEG-4 contents are not used for PDA but desktop, it seems not to be played on PDA where needs low power consumption, limited memory capability and GUI, and so on. In this paper, we propose the adaptation techniques, which can present the MPEG-4 contents on PDA, using scene composition with MPEG-4. The proposed scheme consists of three subparts: physical adaptation, variation adaptation and resource adaptation. Physical adaptation adjusts the physical difference of between the authoring environment and playback environment. Event adaptation part transforms events used for desktop to the events used for playback on PDA. The resource adaptation enables efficiency of playback to promote by using the essential information table on BIFS parser. As the proposed scheme is applied to MPEG-4 player, we see that the MPEG-4 contents are efficiently played on PDA.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.225-231
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• 2002

The physicochemical characteristics of pine nuts gruel were investigated to find the effects of processing condition during the processing. Three-dimensional response surface methodology was applied to investigate effects of ratio of water volume and pine nuts weight to rice weight and heating time on dependent variables of the physicochemical characteristics. The dependent variables in physicochemical characteristics were viscosity (cP), spreadability (cm), pH, soluble solid content (%), color, total sugar (%) and amylose content (%). The F-value of ratio of water volume and pine nuts weight to rice weight and heating time to viscosity were 8.91, 4.54 and 5.02 respectively and they are significantly different at 5% level. The F-value to spreadability were 5.44, 7.88 and 8.04 respectively and they are significantly different at 5% level. These results suggest that water volume, pine nuts weight and heating time greatly affect the viscosity and spreadability of pine nuts gruel. The processing condition also affect the soluble solid content. The changes of the processing condition did not affect the pH of pine nuts gruel. We found that the L, a, b value were affected more by ratio of water volume and pine nuts weight to rice weight than by heating time. The water volume affected more the total sugar and amylose content of pine nuts gruel than pine nuts weight and heating time.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.2
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• pp.97-104
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• 2015

Due to the introduction of various IT devices, including the recently smartphones and the widespread use of the car navigation system to the location-based information service space has been increased. Spatial information users have been requiring higher levels of quality. In this paper, we study how to build accurate three-dimensional space information by integrating MMS(Moblie Mapping System) survey and airborne survey data. Thus, to analyze the tendency of deviation between the MMS survey and airborne survey data observed in the experimental region, the deviation tendency of the data, it was confirmed that was not consistent. Deviation correction model to select how to change the georeferencing information directly contained in the GPS/INS processing results for the determination, classifies the standard is a method for acquiring the correction reference point coordinates using the calibration model, and analyzed their advantages and disadvantages. With the information of the reference point obtained by airborne photograph of a project, using the method of correcting the MMS survey data. Not only clear the deviation existing between the MMS survey data, it was possible to confirm that the deviation exists between the airborne survey data and MMS survey data was also almost erased.

• Journal of the Korean Geotechnical Society
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• v.18 no.3
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• pp.51-59
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• 2002

This paper deals with development of a damage risk assessment system for adjacent buildings to under-passing tunnel face considering 3D-ground movement. The system consists of building and ground information module, monitoring data module, settlement evaluation module, and building damage risk assessment module. The major modules, settlement evaluation module and building damage assessment module, are based on settlement estimation model suggested by Attewell et al (1982) and the building damage assessment method by Mair et al. (1996). After estimating 3D-ground movements due to tunneling with settlement evaluation module, damage assessment far buildings is performed using building damage risk assessment module. The developed system has two major functions; 1) calculation of 3D-settlement with ground loss ($V_{s}$)or maximum settlement ($w_{max}$) and inflection point (i) using various empirical formulae, monitoring data, numerical results, and so on; 2) assessment of damage risk for adjacent buildings of arbitrary section with position change of tunnel face. The field data given by Boscadin and Cording (1989) leer the case of two-storied masonry building near the Metro tunnel in Washington D.C. was simulated to verify the applicability of the developed system.

• Imaging Science in Dentistry
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• v.36 no.2
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• pp.89-94
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• 2006

Purpose : To evaluate clinical usefulness of facial soft tissue thickness measurement using 3D computed tomographic images. Materials and Methods : One cadaver that had sound facial soft tissues was chosen for the study. The cadaver was scanned with a Helical CT under following scanning protocols about slice thickness and table speed; 3 mm and 3 mm/sec, 5 mm and 5 mm/sec, 7 mm and 7 mm/sec. The acquired data were reconstructed 1.5, 2.5, 3.5 mm reconstruction interval respectively and the images were transferred to a personal computer. Using a program developed to measure facial soft tissue thickness in 3D image, the facial soft tissue thickness was measured. After the ten-time repeation of the measurement for ten times, repeated measure analysis of variance (ANOVA) was adopted to compare and analyze the measurements using the three scanning protocols. Comparison according to the areas was analyzed by Mann-Whitney test. Results : There were no statistically significant intraobserver differences in the measurements of the facial soft tissue thickness using the three scanning protocols (p>0.05). There were no statistically significant differences between measurements in the 3 mm slice thickness and those in the 5 mm, 7 mm slice thickness (p>0.05). There were statistical differences in the 14 of the total 30 measured points in the 5 mm slice thickness and 22 in the 7 mm slice thickness. Conclusion : The facial soft tissue thickness measurement using 3D images of 7 mm slice thickness is acceptable clinically, but those of 5 mm slice thickness is recommended for the more accurate measurement.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.2
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• pp.114-121
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• 2011

Introduction: The aim of this study was to demonstrate that the simulation surgery on rapid prototype (RP) model, which is based on the 3-dimensional computed tomography (3D CT) data taken before surgery, has the same accuracy as traditional orthograthic surgery with an intermediate splint, using an optoelectronic tracking navigation system. Materials and Methods: Simulation surgery with the same treatment plan as the Le Fort I osteotomy on the patient was done on a RP model based on the 3D CT data of 12 patients who had undergone a Le Fort I osteotomy in the department of oral and maxillofacial surgery, Seoul National University Dental Hospital. The 12 distances between 4 points on the skull, such as both infraorbital foramen and both supraorbital foramen, and 3 points on maxilla, such as the contact point of both maxillary central incisors and mesiobuccal cuspal tip of both maxillary first molars, were tracked using an optoelectronic tracking navigation system. The distances before surgery were compared to evaluate the accuracy of the RP model and the distance changes of 3D CT image after surgery were compared with those of the RP model after simulation surgery. Results: A paired t-test revealed a significant difference between the distances in the 3D CT image and RP model before surgery.(P<0.0001) On the other hand, Pearson's correlation coefficient, 0.995, revealed a significant positive correlation between the distances.(P<0.0001) There was a significant difference between the change in the distance of the 3D CT image and RP model in before and after surgery.(P<0.05) The Pearson's correlation coefficient was 0.13844, indicating positive correlation.(P<0.1) Conclusion: Theses results suggest that the simulation surgery of a Le Fort I osteotomy using an optoelectronic tracking navigation system I s relatively accurate in comparing the pre-, and post-operative 3D CT data. Furthermore, the application of an optoelectronic tracking navigation system may be a predictable and efficient method in Le Fort I orthognathic surgery.

• Imaging Science in Dentistry
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• v.38 no.4
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• pp.203-208
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• 2008

Purpose : The purpose of this study was to develop a system for the measurement and simulation of the TMJ movement and to analyze the mandibular movement quantitatively. Materials and Methods : We devised patient-specific splints and a registration body for the TMJ movement tracking. The mandibular movements of the 12 subjects with facial deformity and 3 controls were obtained by using an optical tracking system and the patient-specific splints. The mandibular part was manually segmented from the CT volume data of a patient. Three-dimensional surface models of the maxilla and the mandible were constructed using the segmented data. The continuous movement of the mandible with respect to the maxilla could be simulated by applying the recorded positions sequentially. Trajectories of the selected reference points were calculated during simulation and analyzed. Results : The selected points were the most superior point of bilateral condyle, lower incisor point, and pogonion. There were significant differences (P<0.05) between control group and pre-surgical group in the maximum displacement of left superior condyle, lower incisor, and pogonion in vertical direction. Differences in the maximum lengths of the right and the left condyle were 0.59${\pm}$0.30 mm in pre-surgical group and 2.69${\pm}$2.63 mm in control group, which showed a significant difference (P<0.005). The maximum of differences between lengths of the right and the left calculated during one cycle also showed a significant difference between two groups (P<0.05). Conclusion : Significant differences in mandibular movements between the groups implies that facial deformity have an effect on the movement asymmetry of the mandible. (Korean J Oral Maxillofac Radiol 2008; 38 : 203-8)

• Imaging Science in Dentistry
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• v.50 no.3
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• pp.227-236
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• 2020

Purpose: Image artifacts caused by patient motion cause problems in cone-beam computed tomography (CBCT) because they lead to distortion of the 3-dimensional reconstruction. This prospective study was performed to quantify patient movement during CBCT acquisition and its influence on image quality. Materials and Methods: In total, 412 patients receiving CBCT imaging were equipped with a wireless head sensor system that detected inertial, gyroscopic, and magnetometric movements with 6 dimensions of freedom. The type and amplitude of movements during CBCT acquisition were evaluated and image quality was rated in 7 different anatomical regions of interest. For continuous variables, significance was calculated using the Student t-test. A linear regression model was applied to identify associations of the type and extent of motion with image quality scores. Kappa statistics were used to assess intra- and inter-rater agreement. Chi-square testing was used to analyze the impact of age and sex on head movement. Results: All CBCT images were acquired in a 10-month period. In 24% of the investigations, movement was recorded (acceleration: >0.10 [m/s²]; angular velocity: >0.018 [°/s]). In all examined regions of interest, head motion during CBCT acquisition resulted in significant impairment of image quality (P<0.001). Movement in the horizontal and vertical axes was most relevant for image quality (R²>0.7). Conclusion: Relevant head motions during CBCT imaging were frequently detected, leading to image quality loss and potentially impairing diagnosis and therapy planning. The presented data illustrate the need for digital correction algorithms and hardware to minimize motion artefacts in CBCT imaging.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.4
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• pp.699-721
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• 1996

브로네마르크가 골유착성 임플랜트를 소개한 이래로, 현재 골유착성 임플랜트에 의한 치료는 안전하고 안정적인 방법으로 여겨지고 있다. 골유착성 임플랜트를 이용한 초기의 치료는 무치악 환자의 저작기능 회복에 중점을 두어 왔다. 그러나 현재는 환자와 시대의 요구에 따라서 심미성이 주요한 관심사가 되었다. 그래서 표준 지대주보다 더 심미적인 지대주 시스템들이 개발되었다. 다양한 직경의 임플랜트 고정체에 관한 임상가들의 요구에 의해 직경 이 큰 고정체가 생산되기 시작했으며, 5mm의 직경을 갖는 고정체가 그 예이다. 골유착성 임플랜트를 사용하여 보철치료를 할 때, 골과 고정체의 계면은 보철물과 지대주에 가해지는 교합력을 인접골에 전달하게 되며, 이것은 계면에 생물학적인 반응을 야기할 수 있다. 임플랜트의 형태는 골흡수와 같은 바람직하지 않은 반응을 일으키지 않도록 고안되어야 하며, 임플랜트 자체가 교합력을 견딜 수 있어야 한다. 그러므로 골유착성 임플랜트 시스템을 임상에 사용하려고 할 때 이것의 생역학적 분석은 반드시 필요하다. 본 연구에서는 삼차원 유한요소분석적 방법을 사용하여 3.75mm직경을 갖는 고정체에 표준 지대주, 이세티콘 지대주, 마이러스콘 지대주를 연결한 모델과 5mm 직경을 갖는 고정체에 표준 지대주를 연결한 모델에 각각 수직하중, 경사하중, 수평하중을 가했을 때의 응력분포를 비교하였다. 본 연구의 결과는 다음과 같다. 1. 모든 모델에서 금나사의 경부, 금원주, 지대주에 응력의 집중이 일어났다. 2. 임플랜트 고정체에서는 고정체 상방 2/3, 그리고 지대주와 접촉하는 고정체 상면에서 응력의 집중이 관찰되었다. 3. 골에서는 상부 피질골에 응력의 집중이 관찰되었으며, 해면골에서는 두드러진 응력의 집중을 보인 부위는 없었으나 고정체의 근단부 주위 해면골에서의 응력값이 비교적 높았다. 4. 5mm 직경의 고정체를 사용하지 않은 모델 중에서, 표준 지대주를 사용한 경우가 가장 응력분산에 유리하였으며 마이러스콘 지대주를 사용한 경우가 가장 불리하였다. 5. 3가지 하중 조건하에서 수평하중과 경사하중의 경우가 수직하중의 경우보다 더 높은 응력값이 관찰되었다. 6. 응력값은 골에서보다 임플랜트 내부에서 훨씬 높았다.

• Journal of the Korean Ceramic Society
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• v.41 no.11
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• pp.851-857
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• 2004

The stabilizing characteristics of heavy metals in the silicate glass (SD), borosilicate glass (BD), and leadsilicate glass (PD) containing Electric Arc furnace (EAF) dust were studied by the Toxic Characterization Leaching Procedure (TCLP) test. Also, the dependence of the amount of EAF dust upon structural changes of SD, BD, and PD glasses and the TCLP results were investigated by the XRD and FT-IR spectroscopy. In the XRD results, all of SD, BD, and PD specimens containing dust up to 30 wt% were amorphous without crystallizing. In the TCLP test, the concentration of heavy metals leached from the glasses increased with the amount of EAF dust added. The SD specimen series showed the lowest heavy metal leaching and the heavy metal leachate of the PD specimens were lower than those of the BD specimens. But, the Pb leaching from the PD specimens was the highest in the PD glass composition due to the high Pb content. The value of oxygen/network former ratio could be used to compare the chemical durability within the same glass series, but not proper to do between the different glass series. Adding the EAF dust to the SD mother glass, decreased the Si-O-Si symmetry and increased the non-bridging oxygen, which weakened the structure and decreased the chemical durability of glasses. In the BD series glasses, the addition of EAF dust caused the structural changes from tetra-borate group to di-borate group and the formation of the 2-dimensional layer structure of pyre- and ortho- borate, which decreased the chemical durability of glasses. It is concluded that SD series glass among the 3 kinds of glasses is the most effective to stabilize the heavy metals of EAF dust.