151 research outputs found
๋ฏธ์ธ ์ฑ๋์์์ ํญ๋ณต๋ ฅ ์ ์ฒด ํ๋ฆ ๋ถ์
ํ์๋
ผ๋ฌธ (์์ฌ) -- ์์ธ๋ํ๊ต ๋ํ์ : ๊ณต๊ณผ๋ํ ํํ์๋ฌผ๊ณตํ๋ถ, 2020. 8. ๋จ์ฌ์ฑ.In this paper, the flow of a polymer microgel, e.g. Carbopol, in microchannel was analyzed in consideration of the effect of microgel size and slip on the wall of microchannel. From the previous flow visualization experiment, we proposed a new system that channels can move in the opposite direction of flow. This not only shows the velocity of particles but also the overall pathlines at microchannel after fully-developed flow.
With a new system and particle tracking velocimetry code, We conduct the study for two direction. First, we compare the velocity profiles obtained from flow visualizations and simulations in the mid-plane of the microchannel. Simulation with constitutive equation obtained from the rheological property did not coincide with velocity profile from visualizations. For example, the experimental results was slower than computation results near the wall. The reason for this phenomenon was explained by drawing pathlines of particles. Additionally, we suggest the method to find parameters for constitutive equations from the small-gap rheometry. When we compared with the results of flow visualization, it was reasonable. velocity profile from flow visualization.
Second, we observe the effect of slip at wall on the velocity profiles. Unlike previous computation, which ruled out the effects of slip, the calculations proceeded with no slip condition. In our study, we consider both no slip condition and slip condition. For the fair comparison between experiment and computation results, we show that simulation with slip condition is close to the experimental results comparing with simulation with no slip condition. When we consider flow in the microchannel, we have to be careful on obtaining rheological property and considering slip condition.์ด ์ฐ๊ตฌ์์๋ ๋ฒฝ์์์ ์ฌ๋ฆฝ ํ์๊ณผ ๋ฏธ์ธ ์์ญ์์์ ๋ง์ดํฌ๋ก์ ค์ ํฌ๊ธฐ ๋น์จ๋ก ์ธํ ํจ๊ณผ๋ฅผ ๊ณ ๋ คํ์ฌ ๋ง์ดํฌ๋ก ์ฑ๋์์์ ์นด๋ณดํ๊ณผ ๊ฐ์ ๊ณ ๋ถ์ ์ฉ์ก์ ํ๋ฆ์ ๋ถ์ํ๊ณ ์ ํ๋ค. ์ด์ ์ ํ๋ฆ ์๊ฐํ ์ฐ๊ตฌ๋ค์์ ๋ ๋์๊ฐ, ๋ง์ดํฌ๋ก ์ฑ๋์ ํ๋ฆ์ ๋ฐ๋ ๋ฐฉํฅ์ผ๋ก ์์ง์ผ ์ ์๋๋ก ์๋ก์ด ์์คํ
์ ๊ตฌ์ถํ์๋ค. ์ด ์์คํ
์ ์
์์ ํ๋ฆ๋ฟ๋ง ์๋๋ผ ๋ง์ดํฌ๋ก ์ฑ๋์ ์ ๋ฐ์ ์ธ ๋ด๋ถ ์
์ ์ด๋๊ฒฝ๋ก ๋ํ ๊ด์ฐฐํ ์ ์๋ค.
์๋ก์ด ์์คํ
๊ณผ ์
์ ์ถ์ ์๋ ์ธก์ ์ฝ๋๋ฅผ ๊ฐ์ง๊ณ ๋ ๊ฐ์ง ๋ฐฉํฅ์ผ๋ก ์ฐ๊ตฌ๋ฅผ ์งํํ๋ค. ์ฒซ ๋ฒ์งธ๋ก, ๊ธฐ์กด ์คํ๋ค๊ณผ ๊ฐ์ด ์ฑ๋ ์ค์์์ ํ๋ฆ ์๊ฐํ๋ฅผ ํตํด ๊ตฌํ ์๋ ํ๋กํ์ผ๊ณผ ์๋ฎฌ๋ ์ด์
๊ฒฐ๊ณผ๋ฅผ ๋น๊ตํ์๋ค. ์ด ๋ ๊ฒฐ๊ณผ๋ ์ผ์นํ์ง ์์๊ณ , ๋ฒฝ ๊ทผ์ฒ์์์ ์ค์ ํ๋ฆ ์๋๊ฐ ์ด๋ก ์ ์ผ๋ก ๊ณ์ฐ๋ ๊ฒฐ๊ณผ๋ณด๋ค ๋๋ ธ๋ค. ์ด ํ์์ ์ด์ ๋ฅผ ์ฑ๋ ๋ด๋ถ ํ๋ฆ ์ ํ๊ด์
์์ ์ด๋๊ฒฝ๋ก๋ฅผ ํตํด ์ค๋ช
ํ์๋ค. ์ถ๊ฐ์ ์ผ๋ก, ์๋ฎฌ๋ ์ด์
์ ํตํด ํ๋ฆ ์๊ฐํ์ ์๋ ํ๋กํ์ผ์ ๋ง๋๋ก ํผํ
ํ ๋, ์ ํฉํ ํ๋ผ๋ฏธํฐ๋ฅผ ๋ ์ค๋ฏธํฐ ๋ฐ์ดํฐ๋ก๋ถํฐ ์ฐพ์๋ผ ์ ์๋ ๊ฐ๋ฅ์ฑ์ ์ ์ํ์๋ค. ๋ ๋ฒ์งธ๋ก, ๋ฒฝ๋ฉด์์์ ์ฌ๋ฆฝ์ผ๋ก ์ธํด ์๋ ํ๋กํ์ผ์ ๋ถํฌ์ ์ฃผ๋ ์ํฅ์ ๋ณด์๋ค. ๊ธฐ์กด ์ฐ๊ตฌ์์๋ ์ฌ๋ฆฝ์ผ๋ก ์ธํด ๋ ํ๋ฌ๊ฐ ์ ๋๋งํผ์ ์ ํ๊ณ no slip condition์ผ๋ก ๊ณ์ฐํ์๋ค. ๊ฐ ๋์ด์์์ ์๋๋ฅผ ๊ตฌํ ํ, ์๋ฎฌ๋ ์ด์
๊ฒฐ๊ณผ์ ํ๋ฆ ์๊ฐํ ์๋ ํ๋กํ์ผ์ ๋์ด๋ณ๋ก ๋น๊ตํด๋ณด์๋ค. ์ด๋ฅผ ํตํด ์ฌ๋ฆฝ์ ๋ฐ์ํ ์๋ฎฌ๋ ์ด์
๊ณ์ฐ๊ฒฐ๊ณผ๊ฐ ์ค์ ์ ์๋ ํ๋กํ์ผ์ ๋น๊ต์ ์๋ง๊ฒ ์์ธกํ ์ ์๋ค๋ ๊ฒ์ ํ์
ํ๋ค. ์์ ๋ง์ดํฌ๋ก์ฑ๋์์์ ํ๋ฆ์ ์์ธกํ๊ธฐ ์ํด์๋ ์์ ๊ฐญ์์ ๊ตฌํ ๋ ์ค๋ฏธํฐ ํ๋ผ๋ฏธํฐ๋ฅผ ํ์ฉํ๊ณ ์ฌ๋ฆฝ์ ๊ณ ๋ คํด์ผํ๋ค.1. Introduction 9
2. Experiment 13
2.1 Fabrication of microchannel 13
2.2 Fluid preparation 14
2.3 Rheology properties 15
2.4 Micro particle tracking velocimetry 16
2.5 Computation 19
3. Results 22
3.1 Rheometer data 22
3.2 Slip velocity function at wall 23
3.3 Mid-plane velocity profile in microchannel 25
3.4 Computation with slip condition 29
4. Final Remarks 30
5. Reference 34Maste
3์ข ๊ตฌ๊ฐ์ค์บ๋์ ์ ํ๋ ๋น๊ต ํ๊ฐ๋ฅผ ์ํ ๋น์์ ์ฐ๊ตฌ
ํ์๋
ผ๋ฌธ(์์ฌ) -- ์์ธ๋ํ๊ต๋ํ์ : ์น๊ณผ๋ํ ์น์๊ณผํ๊ณผ, 2023. 2. ์๋ฒ์.As a result of the technological advances, digitalization is being applied in various areas of dentistry. As intraoral scanners are widely used for digital impression with the advantage of being easy to use and comfortable for patients, many studies are being conducted. However, new intraoral scanners with various mechanisms and characteristics are constantly pouring out, and comparative evaluation for clinical application is continuously needed. The purpose of this study is to evaluate and verify the performance of the intraoral scanner through trueness and precision comparison.
In this study, trueness and precision are evaluated for the accuracy comparison of intraoral scanners (ISO 5725). The object was designed with the CAD software (SolidworksTM 2016, 3D Systems SolidWorks Corp., Waltham, MA, USA) and the model was fabricated from the NextDent C&B MFH (3D Systems, Rockhill, USA) using the 3D printer (NextDent 5100, 3D Systems, Rockhill, SC, USA). Inlay, Onlay and three-unit Bridge were produced by representing deep and narrow forms frequently used in clinical practice, and the same resin model was used in all experimental groups. Three types of intraoral scanners were evaluated: TRIOS 4ยฎ (3 Shape, Copenhagen, Denmark), I500 (Medit Co, Seoul, South Korea), COMFORT+ (DDS, Seoul, South Korea), and five scan data were obtained by the same trained researcher for consistency. The acquired data was superimposed with the reference data by the 'best-fit alignment' of the Geomagic Control XTM (3D Systems, Rock Hill, SC, USA) software, and the tolerance range was set to ยฑ30ฮผm for 3D comparison to calculate RMS (Root Mean Square). For comparison, the one-way ANOVA and Bonferroni t-test were performed with a significance level of 0.05.
For trueness, the RMS values in the Inlay (36.32ฮผm~37.22ฮผm) model increased in the order of TRIOS4, COMFORT+, and I500, but the trueness tended to decrease. In Onlay (35.98ฮผm~37.22ฮผm) and three-unit Bridge (52.24ฮผm~ 56.64ฮผm) models, RMS values increased in order of I500, TRIOS4, and COMFORT+, but the trueness tended to decrease. But no significance was found between each scanner group on the All pairwise multi-analysis Bonferroni t-test (p>0.05). For precision, there was a significant difference between TRIOS4 and I500, I500 and COMFORT+ in the Inlay model (respectively p=0.027, p<0.001). In the Onlay and three-unit Bridge models, a significant difference was found between COMFORT+ and the remaining two intraoral scanners (TRIOS4, I500).
Trueness and precision are lowered if the optimal distance between the scanner and the model is not maintained due to the narrow and deep part such as a three-unit bridge or the insufficient space between the units. Thus, errors tend to accumulate when the scan range increases. This study provides accuracy information on intraoral scanners, contributing to decision making it offer a view on which intraoral scanners is appropriate for use.๋ณธ ์ฐ๊ตฌ์์๋ ์ต๊ทผ ์๊ฐ๋ ๊ตฌ๊ฐ์ค์บ๋์ ์ง์ค๋ (trueness) ๋ฐ ์ ๋ฐ๋ (precision) ๋น๊ต๋ฅผ ํตํด ์ค์บ๋ ์์ฒด ์ ํ๋ (accuracy) ๋ฑ์ ์ฑ๋ฅ์ ๋ํ์ฌ ํ๊ฐํ๊ณ ๊ฒ์ฆํ๊ณ ์ ํ์๋ค.
ISO 5725๋ฅผ ์ฐธ๊ณ ํ์ฌ ๊ตฌ๊ฐ์ค์บ๋์ ์ ํ๋ ๋น๊ต๋ฅผ ์ํด ์ง์ค๋ ๋ฐ ์ ๋ฐ๋๋ฅผ ํ๊ฐํ์๋ค. ์ง์ค๋๋ ๋ชจ๋ธ์ค์บ๋๋ก ์ธก์ ํ ์ฐธ์กฐ ๋ฐ์ดํฐ์ ๋ํ์ฌ ๊ตฌ๊ฐ์ค์บ๋๋ก ์ธก์ ํ ๋น๊ต ๋ฐ์ดํฐ ๊ฐ์ ์ฐจ์ด๋ฅผ ๋ํ๋ด๋ ๊ฐ์ด๋ฉฐ, ์ ๋ฐ๋๋ 3 ์ข
๋ฅ์ ๊ตฌ๊ฐ์ค์บ๋๋ฅผ ์ด์ฉํด ๋ฐ๋ณตํ์ฌ ์ป์ ๋ฐ์ดํฐ๋ฅผ ์๋ก ์ค์ฒฉํ์ฌ ์ป์ ์ค์ฐจ ๊ฐ์ด๋ค. CAD ์ํํธ์จ์ด์ธ Solidworks 2016TM (Dassault Systรจmes SolidWorks Corp., Waltham, MA, USA) ์ผ๋ก ๋ชจ๋ธ์ ์ค๊ณํ์๊ณ , NextDent C&B MFH (3D Systems, RockHill, SC, USA) 3D ํ๋ฆฐํ
๋ ์ง์ผ๋ก NextDent 5100 (3D Systems, RockHill, SC, USA) 3D ํ๋ฆฐํฐ๋ฅผ ์ด์ฉํ์ฌ ๋ชจ๋ธ๋ก ์ ์ํ์๋ค. ์์์์ ์์ฃผ ์ฐ์ด๋ ๊น๊ณ ์ข์ ํํ ๋ฑ์ ์ฌํํ์ฌ ์ธ๋ ์ด, ์จ๋ ์ด ๋ฐ 3๋ณธ-๋ธ๋ฆฟ์ง ๋ชจ๋ธ์ ์ ์ํ์์ผ๋ฉฐ, ๋ชจ๋ ์คํ๊ตฐ์์ ๋์ผํ ๋ ์ง ๋ชจ๋ธ์ ์ฌ์ฉํ์ฌ ์ ํ ๋น๊ต ํ๊ฐ์ ์ฉ์ดํ์๋ค. ๋ํ, ๋ณธ ๋
ผ๋ฌธ์์๋ TRIOS4 (3 Shape, Copenhagen, Denmark), I500 (Medit Co, Seoul, South Korea), COMFORT+ (DDS, Seoul, South Korea) 3๊ฐ์ง ์ข
๋ฅ์ ๊ตฌ๊ฐ์ค์บ๋๋ฅผ ํ๊ฐํ์๋๋ฐ, ์ผ๊ด์ฑ์ ์ํด ์๋ จ๋ ๋์ผํ ์ฐ๊ตฌ์์ ์ํด ๊ฐ๊ฐ 5๊ฐ์ ์ค์บ ๋ฐ์ดํฐ๋ฅผ ์ฑ๋ํ์๋ค. ์ฑ๋๋ ๋ฐ์ดํฐ๋ Geomagic Control XTM (3D Systems, RockHill, SC, USA) ์ํํธ์จ์ด์ ์ต์ ์ ํฉ ์ค์ฒฉ๋ฒ(๋ฒ ์คํธ-ํ ์ ๋ ฌ)์ ํตํด ์ฐธ์กฐ ๋ฐ์ดํฐ์ ์ค์ฒฉํ์๊ณ , 3D ๋น๊ต ์ ํ์ฉ๋ฒ์๋ ยฑ30ฮผm์ผ๋ก ์ค์ ํ์ฌ RMS (Root Mean Square) ๋ฅผ ์ฐ์ถํ์๋ค. ์ง์ค๋์ ์ ๋ฐ๋ ๋น๊ต๋ฅผ ์ํด ์ ์์์ค 0.05๋ฅผ ๊ธฐ์ค์ผ๋ก ์ผ์๋ถ์ฐ๋ถ์, Bonferroni test๋ก ํต๊ณ ๋ถ์ํ์๋ค.
์ง์ค๋์ ๊ฒฝ์ฐ, ์ธ๋ ์ด ๋ชจ๋ธ์์ RMS ๊ฐ์ 36.32ฮผm~37.22ฮผm์ ๊ฑธ์ณ TRIOS4, COMFORT+, I500 ์์ผ๋ก ์ปค์ง๋ฉฐ ์ง์ค๋๊ฐ ๋ฎ์์ง๋ ๊ฒฝํฅ์ ๋ณด์๋ค. ์จ๋ ์ด์ 3๋ณธ-๋ธ๋ฆฟ์ง ๋ชจ๋ธ์์ RMS ๊ฐ์ ๊ฐ๊ฐ 35.98ฮผm~37.22ฮผm์ 52.24ฮผm~56.64ฮผm๋ฅผ ๋ณด์์ผ๋, ์ผ์๋ถ์ฐ๋ถ์ ํ ๋ค์ค๋น๊ต๋ถ์ Bonferroni t-test์์ ๋ชจ๋ ๋ชจ๋ธ์ ์์ด ๊ตฌ๊ฐ์ค์บ๋ ์ข
๋ฅ์ ๋ฐ๋ฅธ ์ง์ค๋ ๊ฐ์ ์ ์ํ ์ฐจ์ด๋ ๋ฐ๊ฒฌ๋์ง ์์๋ค.
์ ๋ฐ๋์ ๊ฒฝ์ฐ, ์ธ๋ ์ด ๋ชจ๋ธ์์ TRIOS4์ I500, I500๊ณผ COMFORT+๊ฐ ์ ์ํ ์ฐจ์ด๊ฐ ์์์ผ๋ฉฐ (๊ฐ๊ฐ p=0.027, p<0.001), ์จ๋ ์ด์ 3๋ณธ-๋ธ๋ฆฟ์ง ๋ชจ๋ธ์์๋ COMFORT+์ ๋๋จธ์ง ๋ ์ข
๋ฅ์ ๊ตฌ๊ฐ์ค์บ๋ (TRIOS4, I500) ์ฌ์ด์์ ์ ์ํ ์ฐจ์ด๋ฅผ ๋ฐ๊ฒฌํ์๋ค. ๊ฒฐ๋ก ์ ์ผ๋ก, 3๋ณธ-๋ธ๋ฆฟ์ง์ ๊ฐ์ด ํญ์ด ์ข๊ณ ๊น์ ๋ถ๋ถ์ ํฌํจํ๊ณ , ๊ตฌ์ฑ ๋จ์(unit) ์ฌ์ด ๊ฐ๊ฒฉ์ด ์ข์ ์ค์บ๋์ ๋ชจ๋ธ ๊ฐ์ ์ต์ ์ ๊ฑฐ๋ฆฌ๊ฐ ํ๋ณด๋์ง ์์ ๊ฒฝ์ฐ ์ง์ค๋์ ์ ๋ฐ๋๋ ๋ฎ์์ง๋ค. ๋ํ์ฌ, ์ค์บ์ ๋ฒ์๊ฐ ๋์ด์ง์๋ก ์ค์ฐจ๋ ์ถ์ ๋์ด ์ ํ๋๋ ๊ฐ์ํ๊ฒ ๋๋ค. ๋ณธ ์ฐ๊ตฌ๋ฅผ ํตํด ๊ตฌ์ถ๋ ์คํ ๋ฐ์ดํฐ๋ฅผ ๊ธฐ๋ฐ์ผ๋ก ์์์์ ์ ์ ํ ๊ตฌ๊ฐ์ค์บ๋์ ์ ํ ๋ฐ ์ค์บ ์ ๋ต์ ๋์๋๊ณ ์ ํ์๋ค.โ
. INTRODUCTION 1
โ
ก. MATERIALS AND METHODS 10
โ
ข. RESULTS 16
โ
ฃ. DISCUSSION 22
โ
ค. CONCLUSIONS 30์
์๋์ ์์ ๋นํ์์ญ๊ณผ ์๋์ ๋ฒ์คํ์ธ ๋คํญ์์ ์ด์ฉํ ๋ค์ ์ฟผ๋๋กํฐ์ ๊ฒฝ๋ก ๊ณํ
ํ์๋
ผ๋ฌธ (์์ฌ) -- ์์ธ๋ํ๊ต ๋ํ์ : ๊ณต๊ณผ๋ํ ๊ธฐ๊ณํญ๊ณต๊ณตํ๋ถ, 2020. 8. ๊นํ์ง.Multi-agent systems consisting of unmanned aerial vehicles (UAVs) are receiving attention from
many industrial domains due to their mobility, and applicability. To safely operate these multiagent
systems, path planning algorithm that can generate safe, dynamically feasible trajectory is
required. However, existing multi-agent trajectory planning methods may fail to generate multiagent
trajectory in obstacle-dense environment due to deadlock or optimization failure caused
by infeasible collision constraints. In this paper, we presents a new e client algorithm which
guarantees a solution for a class of multi-agent trajectory planning problems in obstacle-dense
environments. Our algorithm combines the advantages of both grid-based and optimization-based
approaches, and generates safe, dynamically feasible trajectories without su ering from an erroneous
optimization setup such as imposing infeasible collision constraints. We adopt a sequential
optimization method with dummy agents to improve the scalability of the algorithm, and utilize
the convex hull property of Bernstein polynomial to replace non-convex collision avoidance constraints
to convex ones. We validate the proposed algorithm through the comparison with our
previous work and SCP-based method. The proposed method reduces more than 50% of the objective
cost compared to our previous work, and reduces more than 75% of the computation time
compared to SCP-based method. Furthermore, the proposed method can compute the trajectory
for 64 agents on average 6.36 seconds with Intel Core i7-7700 @ 3.60GHz CPU and 16G RAM.๋ฌด์ธ๋นํ์ฒด(UAV)๋ก ๊ตฌ์ฑ๋ ๋ค์ค ์์ด์ ํธ ์์คํ
์ ๋์ ๊ธฐ๋์ฑ ๋ฐ ์์ฉ ๊ฐ๋ฅ์ฑ์ผ๋ก ๋ง์ ์ฐ์
๋ถ์ผ์์ ๊ด์ฌ์ ๋ฐ๊ณ ์๋ค. ์ด๋ฌํ ๋ค์ค ์์ด์ ํธ ์์คํ
์ ์์ ํ๊ฒ ์ด์ฉํ๋ ค๋ฉด ์์ ํ๊ณ ๋์ ์ผ๋ก ์คํ ๊ฐ๋ฅ ๊ฒฝ๋ก๋ฅผ ์์ฑํ ์ ์๋ ๊ฒฝ๋ก ๊ณํ ์๊ณ ๋ฆฌ์ฆ์ด ํ์ํ๋ค. ๊ทธ๋ฌ๋ ๊ธฐ์กด์ ๋ค์ค ์์ด์ ํธ ๊ฒฝ๋ก ๊ณํ ๋ฐฉ๋ฒ์ ์ฅ์ ๋ฌผ ํ๊ฒฝ์์ ๊ต์ฐฉ ์ํ๋ ๋ถ์ ์ ํ ์ถฉ๋ ํํผ ์กฐ๊ฑด์ผ๋ก ์ธํ ์ต์ ํ ์คํจ๊ฐ ์ผ์ด๋ ์ ์๋ค๋ ํ๊ณ๊ฐ ์๋ค.
๋ณธ ๋
ผ๋ฌธ์์๋ ์ฅ์ ๋ฌผ ํ๊ฒฝ์์ ํด์ ์กด์ฌ๋ฅผ ๋ณด์ฅํ๋๋ก ๋ค์ค ์์ด์ ํธ ๊ฒฝ๋ก ๊ณํ ๋ฌธ์ ๋ฅผ ๋ณํํ ๋ค ์ด๋ฅผ ํจ์จ์ ์ผ๋ก ํ์ด๋ผ ์ ์๋ ์๋ก์ด ๊ฒฝ๋ก ๊ณํ ์๊ณ ๋ฆฌ์ฆ์ ์ ์ํ๋ค. ์ด ์๊ณ ๋ฆฌ์ฆ์ ๊ทธ๋ฆฌ๋ ๊ธฐ๋ฐ ์ ๊ทผ๋ฒ๊ณผ ์ต์ ํ ๊ธฐ๋ฐ ์ ๊ทผ๋ฒ์ ์ฅ์ ์ ๋ชจ๋ ๊ฐ์ง๋๋ก ์ค๊ณ๋์์ผ๋ฉฐ, ๋ถ๊ฐ๋ฅํ ์ถฉ๋ ๊ตฌ์์กฐ๊ฑด์ ๋ถ๊ณผํ์ง ์๊ณ ์์ ํ๊ณ ๋์ ์ผ๋ก ์คํ ๊ฐ๋ฅํ ๊ถค์ ์ ์์ฑํ ์ ์๋ค. ์ด ์๊ณ ๋ฆฌ์ฆ์ ๋๋ฏธ ์์ด์ ํธ(dummy agents)์ ์ด์ฉํ ์์ฐจ ์ต์ ํ ๋ฐฉ๋ฒ์ ์ฌ์ฉํ์ฌ ์๊ณ ๋ฆฌ์ฆ์ ํ์ฅ์ฑ(scalability)์ ๋์์ผ๋ฉฐ, ๋ฒ์คํ์ธ(Bernstein) ๋คํญ์์ ๋ณผ๋ก ๊ป์ง(convex hull) ์ฑ์ง์ ํ์ฉํ์ฌ ๋ณผ๋กํ์ง ์์ ์ถฉ๋ ํํผ ์ ์ฝ ์กฐ๊ฑด์ ๋ณผ๋กํํ์๋ค.
์ ์๋ ์๊ณ ๋ฆฌ์ฆ์ ์ฑ๋ฅ์ ์ ํ ์ฐ๊ตฌ์ SCP ๊ธฐ๋ฐ ๋ฐฉ๋ฒ๊ณผ์ ๋น๊ต๋ฅผ ํตํด ๊ฒ์ฆ๋์๋ค. ์ ์๋ ๋ฐฉ๋ฒ์ ์ ํ ์ฐ๊ตฌ์ ๋นํด ๋ชฉํ ๋น์ฉ์ 50% ์ด์ ์ ๊ฐํ์์ผ๋ฉฐ, SCP ๊ธฐ๋ฐ ๋ฐฉ๋ฒ์ ๋นํด ๊ณ์ฐ ์๊ฐ์ 75% ์ด์ ๊ฐ์ํ์๋ค. ๋ํ ์ ์๋ ๋ฐฉ๋ฒ์ ์ธํ
์ฝ์ด i7-7700 @ 3.60GHz CPU ๋ฐ 16G RAM ํ๊ฒฝ์์ 64๊ฐ ์์ด์ ํธ์ ๊ถค์ ์ ๊ณ์ฐํ๋๋ฐ ํ๊ท 6.36์ด๊ฐ ์์๋๋ค.1 Introduction 1
1.1 Literature review 2
1.2 Thesis contribution 3
1.3 Thesis outline 3
2 Bernstein polynomial 4
2.1 Definition 4
2.2 Properties 5
2.2.1 Convex hull property 5
2.2.2 Endpoint interpolation property 5
2.2.3 Arithmetic operations and derivatives 6
3 Multi-agent trajectory optimization 7
3.1 Problem formulation 7
3.1.1 Assumption 7
3.1.2 Trajectory Representation 8
3.1.3 Objective function 9
3.1.4 Convex constraints 9
3.1.5 Non-convex collision avoidance constraints 10
3.2 Collision constraints construction 11
3.2.1 Initial trajectory planning 12
3.2.2 Safe flight corridor 14
3.2.3 Relative safe flight corridor 16
3.3 Trajectory optimization 18
4 Sequential optimization with dummy agents 20
5 Experimental results 24
5.1 Comparison with the previous work 24
5.1.1 Success rate 25
5.1.2 Solution quality 26
5.1.3 Scalability analysis 26
5.2 Comparison with SCP-based method 27
5.3 Flight test 29
6 Conclusion 31Maste
Triple antibiotics์ ๊ด๋ จํ ์น์ ๋ณ์์ ์๋ฐฉ
Regenerative endodontics has a potential to heal a partially necrotic pulp, which can be beneficial for the continued root development and strengthening of immature teeth. For this purpose, triple antibiotic mixture of ciprofloxacin, metronidazole, and minocycline was recommended as intracanal medicament in an attempt to disinfect the root canal system for revascularization of a tooth with a necrotic pulp. However, discoloration of the tooth was reported after applying this. This case shows the idea for preventing the tooth discoloration using a delivery syringe (SW-O-01, Shinwoo dental) to avoid the contact between the clinical crown and the antibiotics.ope
The First Case Series of Cryopyrin-Associated Periodic Syndrome in Korea
Cryopyrin-associated periodic syndrome (CAPS) is a hereditary autoinflammatory syndrome caused by mutations in NLRP3 (encoding cryopyrin), which presents with fever, fatigue and arthralgia. Thus far, however there have been no reports of CAPS in Korea. Herein, we report 3 cases of CAPS for the first time in Korea. The first case, a 28-year-old man with recurrent urticaria, arthralgia and fever induced by cold, all of which were observed in his father, showed elevated erythrocyte sedimentation rate and C-reactive protein. He exhibited a p.Gly303Asp variant of the NLPR3 gene. The second case, a 2-year-old girl who had recurrent urticaria, arthritis and oral and genital ulcers, was positive for HLA B51 and a p.Glu569Lys mutation in exon 3 of the NLRP3 gene. Administration of anakinra greatly improved her symptoms. The third case, a 4-year-old boy who presented with recurrent urticaria, arthralgia, and fever, exhibited a p.Val72Met mutation in exon 1 of the NLRP3 gene. Administration of tocilizumab improved all of his symptoms. This small case series suggests that clinicians consider CAPS and conduct genetic studies when arthralgia and fever are accompanied by urticaria in Korea.ope
Comparison of bond strengths of ceramic brackets bonded to zirconia surfaces using different zirconia primers and a universal adhesive
Objectives: The aim of this study is to compare the shear bond strengths of ceramic brackets bonded to zirconia surfaces using different zirconia primers and universal adhesive. Materials and Methods: Fifty zirconia blocks (15 x 15 x 10 mm, Zpex, Tosoh Corporation) were polished with 1,000 grit sand paper and air-abraded with 50 microm Al2O3 for 10 seconds (40 psi). They were divided into 5 groups: control (CO), Metal/Zirconia primer (MZ, Ivoclar Vivadent), Z-PRIME Plus (ZP, Bisco), Zirconia Liner (ZL, Sun Medical), and Scotchbond Universal adhesive (SU, 3M ESPE). Transbond XT Primer (used for CO, MZ, ZP, and ZL) and Transbond XT Paste was used for bracket bonding (Gemini clear ceramic brackets, 3M Unitek). After 24 hours at 37 degrees C storage, specimens underwent 2,000 thermocycles, and then, shear bond strengths were measured (1 mm/min). An adhesive remnant index (ARI) score was calculated. The data were analyzed using one-way analysis of variance and the Bonferroni test (p = 0.05). Results: Surface treatment with primers resulted in increased shear bond strength. The SU group showed the highest shear bond strength followed by the ZP, ZL, MZ, and CO groups, in that order. The median ARI scores were as follows: CO = 0, MZ = 0, ZP = 0, ZL = 0, and SU = 3 (p < 0.05). Conclusions: Within this experiment, zirconia primer can increase the shear bond strength of bracket bonding. The highest shear bond strength is observed in SU group, even when no primer is used.ope
Probe-based confocal laser endomicroscopy in the differential diagnosis of inflammatory bowel diseases:
ope
Effect of moisture and drying time on the bond strength of the one-step self-etching adhesive system
OBJECTIVES: To investigate the effect of dentin moisture degree and air-drying time on dentin-bond strength of two different one-step self-etching adhesive systems.
MATERIALS AND METHODS: Twenty-four human third molars were used for microtensile bond strength testing of G-Bond and Clearfil S(3) Bond. The dentin surface was either blot-dried or air-dried before applying these adhesive agents. After application of the adhesive agent, three different air drying times were evaluated: 1, 5, and 10 sec. Composite resin was build up to 4 mm thickness and light cured for 40 sec with 2 separate layers. Then the tooth was sectioned and trimmed to measure the microtensile bond strength using a universal testing machine. The measured bond strengths were analyzed with three-way ANOVA and regression analysis was done (p = 0.05).
RESULTS: All three factors, materials, dentin wetness and air drying time, showed significant effect on the microtensile bond strength. Clearfil S(3) Bond, dry dentin surface and 10 sec air drying time showed higher bond strength.
CONCLUSIONS: Within the limitation of this experiment, air drying time after the application of the one-step self-etching adhesive agent was the most significant factor affecting the bond strength, followed by the material difference and dentin moisture before applying the adhesive agent.ope
Influence of additional etching on shear bond strength of self-etching adhesive system to enamel
Recently, self-etching adhesive system has been introduced to simplify the clinical bonding procedures. It is less acidic compared to the phosphoric acid, thus there is doubt whether this system has enough bond strength to enamel. The purpose of this study was to investigate the influence of additional etching on the adhesion of resin composite to enamel.
Ninety extracted bovine permanent anterior teeth were used. The labial surfaces of the crown were ground with 600-grit abrasive paper under wet condition. The teeth were randomly divided into six groups of 15 teeth each. Clearfil SE Bondยฎ, Adperโข Prompt L-Pop and Tyrian SPEโข were used as self-etching primers. Each self-etching primers were applied in both enamel specimens with and without additional etching. For additional etching groups, enamel surface was pretreated with 32% phosphoric acid (UNI-ETCH, Bisco, Inc., Schaumburg, IL, USA). Hybrid resin composite Clearfil AP-X, (Kuraray Co., Ltd., Osaka, Japan) was packed into the mold and light-cured for 40 seconds. Twenty-four hours after storage, the specimens were tested in shear bond strength. The data for each group were subjected to independent t - test at p < 0.01 to make comparisons among the groups.
In Clearfil SE Bondยฎ, shear bond strength of additional etching group was higher than no additional etching group (p 0.01).
In conclusion, self-etching adhesive system with weak acid seems to have higher bond strength to enamel with additional etching, while self-etching adhesive system with strong acid seems not.ope
Enrique Dussel. 1492. El encubrimiento del Otro. Hacia el mito
์ด ์ฑ
์ ํด๋ฐฉ ์ ํ์๋ก ์ฐ๋ฆฌ์๊ฒ ๋ ์
์๋ ค์ง ์๋ฆฌ์ผ ๋์
์ด ์๋ฉ๋ฆฌ์นด ๋๋ฅ ๋ฐ๊ฒฌ
์ค๋ฐฑ์ฃผ๋
์ด ๋๊ธฐ ์ผ๋ง ์ ์ธ 1992๋
๋
์ผ ํ
๋ํฌํธ๋ฅดํธ์์ ํํ ๊ฐ์ฐ๋ฌธ์ ์ฑ
์ผ๋ก ์ฎ์ด
๋ธ ๊ฒ์ด๋ค. ํฌ์คํธ๋ชจ๋๋์ฆ์ด๋ผ๋ ์ฉ์ด๋
์ด์ ํ๋ฌธ์ ์ ํ์ ๋ค์์ผ๋ก ์ฌ๋ผ์ ธ๊ฐ๋
์ฆ์, ๋ค์ ๊ทผ๋๋ฅผ ๋
ผํ๋ ์ด ์ฑ
์ ๋ํด์,
ํนํ ๋ผํด์๋ฉ๋ฆฌ์นด ๋งฅ๋ฝ์ ํ๊ตฌํ ๊ทธ์ ์
์์ ์ง๊ธ ํ๊ตญ์์ ์ฝ๋ ์ด์ ๋ ๋ฌด์์ผ๊น?.
- โฆ