• 한국측량학회지
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• 제38권6호
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• pp.521-531
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• 2020

QZSS (Quasi-Zenith Satellite System)는 위성의 L6 밴드를 통해서 CLAS (Centimeter Level Augmentation Service)를 제공한다. CLAS는 현재 GPS (Global Positioing System), Galileo 그리고, QZSS 위성군에 대한 보정정보를 제공하며, 이러한 보정정보를 C-SSR (Compact - Space State Representation)라고 한다. 본 연구에서는 L6 밴드를 수신할 수 있는 GPS 수신기인 Septentrio의 AsteRx4를 이용하여 CLAS 메시지를 수신하고, 그 메시지를 디코딩하여 C-SSR을 획득하였다. 그리고, GPS, Galileo, QZSS의 코드의사거리 관측치에 Compact SSR을 적용하여 GNSS (Global Navigation Satellite System) 오차를 보정하고, 비선형 최소제곱법으로 수신기의 3차원 위치 및 위성군의 시계오차들을 추정하는 다중 위성항법 기반의 Code-PPP (Precise Point Positioning)를 개발하였다. 개발한 알고리즘의 정확도를 평가하기 위해서 IGS (International GNSS Service) 사이트 중 하나인 TSK2 (Tsukuba)를 대상으로 정지측위를 수행하고, 일본의 가와니시(Kawanishi)시의 이나강(Ina river) 주변을 주행하며 이동측위를 수행하였다. 그 결과, 정지측위의 경우 모든 데이터셋의 평균 RMSE (Root Mean Squared Error)는 수평방향으로 0.35 m, 수직방향으로 0.57 m의 정확도를 나타냈다. 그리고 이동측위의 경우 VRS의 RTK-FIX 값과 비교해 봤을 때 수평방향은 약 0.82 m, 수직방향은 약 3.56 m의 정확도를 나타냈다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2011년도 학술발표회
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• pp.17-17
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• 2011

As a method of countermeasure to bed degradation and armoring phenomena of bed material in the downstream area of dam reservoirs, sediment augmentation (replenished sediment) has been carried out in many Japanese rivers. In general, bed of the replenished sediment site is composed of rocks, because the site is located in the downstream area of the dams and sediment supply is very small. Bed deformation process has been researched by many researchers. As a method of countermeasure to bed degradation and armoring phenomena of bed material in the downstream area of dam reservoirs, sediment augmentation (replenished sediment) has been carried out in many Japanese rivers. In general, bed of the replenished sediment site is composed of rocks, because the site is located in the downstream area of the dams and sediment supply is very small. Bed deformation process has been researched by many researchers. However, most of them can treat movable bed only and cannot be applied to the bed deformation process of sediment on rocks. If the friction angle between the sediment and the bed surface is assumed to be the same as the friction angle between the sediment and the sediment, sediment transport rate must be smaller without sediment deposition layer on the rocks. As a result, the reproduced bed geometry is affected very well. In this study, non-equilibrium transport process of non-cohesive sediment on rigid bed is introduced into the horizontal two dimensional bed deformation model and the model is applied to the erosion process of replenished sediment on rock in the Nakagawa, Japan. Here, the Japanese largest scale sediment augmentation has been performed in the Nakagawa. The results show that the amounts of the eroded sediment and the remained sediment reproduced by the developed numerical model are $56300m^3$ and $26800m^3$, respectively. On the other hand, the amounts of the eroded sediment and the remained sediment measured in the field after the floods are $56600m^3$ and $26500m^3$, respectively. The difference between the model and field data is very small. Furthermore, the bed geometry of the replenished sediment after the floods reproduced by the developed model has a good agreement with the measured bed geometry after the floods. These results indicate that the developed model is able to simulate the erosion process of replenished sediment on rocks very well. Furthermore, the erosion speed of the replenished sediment during the decreasing process of the water discharge is faster than that during the increasing process of the water discharge. The replenished sediment is eroded well, when the top of the replenished sediment is covered by the water. In general, water surface level is kept to be high during the decreasing process of the discharge during floods, because water surface level at the downstream end is high. Hence, it is considered that the high water surface level during the decreasing process of the water discharge affects on the fast erosion of the replenished sediment.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제41권
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• pp.33.1-33.7
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• 2019

Background: The concept of the ideal morphology for the alveolar bone form is an important element to reconstruct or restore the in maximizing esthetic profile and functional alveolar bone restoration. The purpose of this preliminary study is to evaluate the normal alveolar bone structure to provide the standard reference and guide template for use in diagnosing for implant placement, determining the correct amount of bone augmentation in actual clinical practice and producing prostheses based on three-dimensional imaging assessment of alveolar bone. Methods: This study was included 11 men and 11 women (average age, 22.6 and 24.5 years, respectively) selected from among 127 patients. The horizontal widths of alveolar bone of maxilla and mandible were measured at the crestal, mid-root, and root apex level on MDCT (multi-detector computed tomography) images reconstructed by medical imaging software. In addition, tooth dimensions of the central incisors, canines, second premolars, and first molars of maxilla and mandible, including the horizontal width of the interdental alveolar bone crest, were also measured and statistically analyzed. Results: The horizontal alveolar bone width of the palatal side of maxilla showed a distinct increment from the alveolar bone crest to the apical region in both anterior and posterior areas. The average widths of the maxillary alveolar ridge were as follows: central incisor, 7.43 mm; canine, 8.91 mm; second premolar, 9.57 mm; and first molar, 12.38 mm. The average widths of the mandibular alveolar ridge were as follows: central incisor, 6.21 mm; canine, 8.55 mm; second premolar, 8.45 mm; and first molar, 10.02 mm. In the buccal side, the alveolar bone width was not increased from the crest to the apical region. The horizontal alveolar bone width of an apical and mandibular border region was thinner than at the mid-root level. Conclusions: The results of the preliminary study are useful as a clinical guideline when determining dental implant diameter and position. And also, these measurements can also be useful during the production of prefabricated membranes and customized alveolar bone scaffolds.

• Journal of Periodontal and Implant Science
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• 제49권1호
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• pp.14-24
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• 2019

Purpose: To assess the influence of using different combinations of guided bone regeneration (GBR) materials on volume changes after wound closure at peri-implant dehiscence defects. Methods: In 5 pig mandibles, standardized bone defects were created and implants were centrally placed. The defects were augmented using different combinations of GBR materials: xenogeneic granulate and collagen membrane (group 1, n=10), xenogeneic granulate and alloplastic membrane (group 2, n=10), alloplastic granulates and alloplastic membrane (group 3, n=10). The horizontal thickness was assessed using cone-beam computed tomography before and after suturing. Measurements were performed at the implant shoulder (HT0) and at 1 mm (HT1) and 2mm (HT2) below. The data were statistically analysed using the Wilcoxon signed-rank test to evaluate within-group differences. Bonferroni correction was applied when calculating statistical significance between the groups. Results: The mean horizontal thickness before suturing was $2.55{\pm}0.53mm$ (group 1), $1.94{\pm}0.56mm$ (group 2), and $2.49{\pm}0.73mm$ (group 3). Post-suturing, the values were $1.47{\pm}0.31mm$ (group 1), $1.77{\pm}0.27mm$ (group 2), and $2.00{\pm}0.48mm$ (group 3). All groups demonstrated a loss of horizontal dimension. Intragroup changes exhibited significant differences in group 1 (P<0.001) and group 3 (P<0.01). Intergroup comparisons revealed statistically significant differences of the relative changes between groups 1 and 2 (P=0.033) and groups 1 and 3 (P=0.015). Conclusions: Volume change after wound closure was minimized by using an alloplastic membrane. The stability of the augmented horizontal thickness was most ensured by using this type of membrane irrespective of the bone substitute material used for membrane support.

• 디자인학연구
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• 제20권3호
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• pp.39-48
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• 2007

본 논문은 도시환경의 공공사인시스템의 효율극대화를 위하여 안구운동을 측정하는 공학 심리적 또는 인지 과학적 실험을 통하여 안구운동과 가로세로의 시각흐름 그리고 유전된 문화적. 선험적 도식 그리고 대뇌의 시각 시스템의 차별을 탐색하였다. 따라서 EMR 관측실험과 bitmap counting 방법을 대입함으로서 가장 효율적인 시각디자인 측정을 구할 수 있는 algorithm을 도출하였다. 본 논문에서는 과학적인 실험 Data가 인간의 $\ulcorner$Schema$\lrcorner$ 와 $\ulcorner$Sensory Qualia$\lrcorner$ 에 의해, 차별화와 시각표집(Visual Sampling)의 가변성(Momentum)이 상존함을 알게 되었다.

• 한국항공우주학회지
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• 제38권7호
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• pp.655-663
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• 2010

DUP(direct underside pressurization)는 위그선이 이륙하기 위하여 수면 위를 항주할때 낮은 속도에서 이륙할 수 있도록 양력을 증가시키는 역할을 한다. 이러한 DUP가 위그선의 안정성과 공기역학적인 힘에 미치는 영향에 관하여 3차원 수치해석을 수행하였다. 해석에 사용된 위그선인 "Aircat"은 동체의 중심에 프로펠러가 있고 동체하부에 공기부양실이 있으며 Lippisch형의 날개와 큰 T자형의 수평꼬리날개를 가지고 있다. 저속에서 대부분의 양력은 프로펠러에 의해 가속된 공기가 동체의 가운데 통로를 통하여 공기부양실로 들어가 정체됨으로써 발생한다. 그러나 DUP에 의해 가속된 공기는 동압의 증가로 인하여 항력을 증가 시킬 뿐만 아니라 안정성에 영향을 주게 된다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제35권1호
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• pp.55-59
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• 2013

In the oral and maxillofacial area, bone defects are created by various reasons and demand for bone grafts, while dental implant implantation has been increased consistently. To solve these problems, there has been development of autogenous tooth-bone graft material (AutoBT$^{(R)}$, Korea Tooth Bank Co., Korea), and we have collected ground reasons to substitute free autobone graft with this material in clinical use. This autogenous tooth-bone graft material is produced in powder type and block type. Block type is useful in esthetic reconstruction of the defect site and vertical and horizontal augmentation of alveolar bone because this type has high strength value, well maintained shape and is less absorbed. Therefore, the author of this study gained favorable result by grafting the block type autogenous tooth-bone graft material after dental implant implantation on the bone defects of the mandibular molar extraction site. Moreover, the author represents this case with literature review after confirming bone remodeling on the computed tomography image and by histological analysis.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.600-605
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• 2004

The road construction with horizontal expansion of country using and augmentation of traffic demand is advanced actively and it accompanies hereupon, the above of 70% of the country is formed at the mountain in our country where the hazard cut slope has been created. In this study, It is prepared a effective management countermeasure of cut slope introduced priority investigation decision method against hazard cut slope which is influenced by abnormally rainfall by an unusual change in the weather such as a guerilla rainfall character. In meaning link, It was executed collapse cause by failure character analysis in the cut slope which has failed for the last five years and it is prepared the hazard grade criterion from E to A grade according to collapse cause. It is decided that a maintenance management grade by the hazard grade classification criterion of cut slope. So It is possible to hazard cut slope. It is established failure protection counter countermeasure by effective maintenance management through the hazard grade c1assification criterion and it will be able to dispose to advanced nation level like Hong Kong and Japanese.

• International Journal of Aeronautical and Space Sciences
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• 제11권4호
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• pp.338-344
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• 2010

This paper discusses the development of the control system of a mini quadrotor in Konkuk University for indoor applications. The attitude control system consists of a stability augmentation system, which acts as the inner loop control, and a modern control approach based on modeling will be implemented as the outer loop. The inner loop control was experimentally satisfied by a proportional-derivative controller; this was used to support the flight test in order to validate the modeling. This paper introduces the mathematical model for the simulation and design of the optimal control on the outer loop control. To perform the experimental tests, basic electronic hardware was developed using simple configurations; a microcontroller used as the embedded controller, a low-cost 100 Hz inertial sensors used for the inertial sensing, infra-red sensors were employed for horizontal ranging, an ultrasonic sensor was used for ground ranging and a high performance propeller system built on an quadrotor airframe was also employed. The results acquired from this compilation of hardware produced an automatic hovering ability of the system with ground control system support for the monitoring and fail-safe system.

• 대한치과의사협회지
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• 제53권8호
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• pp.545-557
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• 2015

The modified ridge splitting/expansion technique combined with guided bone regeneration (GBR) for implant surgery is used to expand the narrow and atrophied edentulous alveolar ridge. Also, the simultaneous implant placement after ridge splitting/expansion technique can reduce the treatment and healing time. This case report includes three patients with a narrow edentulous alveolar ridge of the 2 to 4mm. All three patients underwent a fracture of thin buccal cortical bone plate, and these defects were corrected by the use of the guided bone regeneration (GBR). After 7 to 18 months, all surgical area was stable, and all implant showed a good healing state on the clinical and radiographic examination. In conclusion, though this surgical method is technique sensitive, the modified ridge splitting/expansion technique combined with GBR for implant surgery is recommended for a horizontal augmentation in the narrow edentulous alveolar ridge.