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스케일불변 특징의 삼차원 재구성을 통한 이동 로봇의 상대위치추정
申東范(Dong-Fan Shen),吉世基(Se-Kee Kil),李鍾實(Jong-Shill Lee),柳劑群(Je-Goon Ryu),李應赫(Eung-Hyuk Lee),洪勝弘(Seung-Hong Hong) 대한전기학회 2006 전기학회논문지 D Vol.55 No.4
A key component of autonomous navigation of intelligent home robot is localization and map building with recognized features from the environment. To validate this, accurate measurement of relative location between robot and features is essential. In this paper, we proposed relative localization algorithm based on 3D reconstruction of scale invariant features of two images which are captured from two parallel cameras. We captured two images from parallel cameras which are attached in front of robot and detect scale invariant features in each image using SIFT(scale invariant feature transform). Then, we performed matching for the two image's feature points and got the relative location using 3D reconstruction for the matched points. Stereo camera needs high precision of two camera's extrinsic and matching pixels in two camera image. Because we used two cameras which are different from stereo camera and scale invariant feature point and it's easy to setup the extrinsic parameter. Furthermore, 3D reconstruction does not need any other sensor. And the results can be simultaneously used by obstacle avoidance, map building and localization. We set 20㎝ the distance between two camera and capture the 3frames per second. The experimental results show ±6㎝ maximum error in the range of less than 2m and ±15㎝ maximum error in the range of between 2m and 4m.
Analysis of Factors Impacting Atmospheric Pressure Plasma Polishing
Ju-Fan Zhang,Bo Wang,Shen Dong 한국정밀공학회 2008 International Journal of Precision Engineering and Vol.9 No.2
Atmospheric pressure plasma polishing (APPP) is a noncontact precision machining technology that uses low temperature plasma chemical reactions to perform atom-scale material removal. APPP is a complicated process, which is affected by many factors. Through a preliminary theoretical analysis and simulation, we confirmed that some of the key factors are the radio frequency (RF) power, the working distance, and the gas ratio. We studied the influence of the RF power and gas ratio on the removal rate using atomic emission spectroscopy, and determined the removal profiles in actual operation using a commercial form talysurf. The experimental results agreed closely with the theoretical simulations and confirmed the effect of the working distance. Finally, we determined the element compositions of the machined surfaces under different gas ratios using X-ray photoelectron spectroscopy to study the influence of the gas ratio in more detail. We achieved a surface roughness of Ra 0.6 ㎚ on silicon wafers with a peak removal rate of approximately 32 ㎣/min.
Analysis of Factors Impacting Atmospheric Pressure Plasma Polishing
Zhang, Ju-Fan,Wang, Bo,Dong, Shen Korean Society for Precision Engineering 2008 International Journal of Precision Engineering and Vol.9 No.2
Atmospheric pressure plasma polishing (APPP) is a noncontact precision machining technology that uses low temperature plasma chemical reactions to perform atom-scale material removal. APPP is a complicated process, which is affected by many factors. Through a preliminary theoretical analysis and simulation, we confirmed that some of the key factors are the radio frequency (RF) power, the working distance, and the gas ratio. We studied the influence of the RF power and gas ratio on the removal rate using atomic emission spectroscopy, and determined the removal profiles in actual operation using a commercial form talysurf. The experimental results agreed closely with the theoretical simulations and confirmed the effect of the working distance. Finally, we determined the element compositions of the machined surfaces under different gas ratios using X-ray photoelectron spectroscopy to study the influence of the gas ratio in more detail. We achieved a surface roughness of Ra 0.6 nm on silicon wafers with a peak removal rate of approximately 32 $mm^{3}$/min.
Association between Fecal Bile Acids and Colorectal Cancer: A Meta-analysis of Observational Studies
Jin Lu Tong,Jun Shen,Guo Quan Fan,Shu Dong Xiao,Zhi Hua Ran 연세대학교의과대학 2008 Yonsei medical journal Vol.49 No.5
Purpose: To provide a systematic review with meta-analysis for addressing the relationship between fecal bile acids (FBAs) and colorectal cancer. Materials and Methods: Electronic databases were searched for all observational studies that examined the relationship between FBAs and colorectal cancer or adenoma, and calculated weighted mean difference (WMD) and 95% confidence interval (CI). Publication bias was assessed with funnel plot. Results: Twenty case-control or cohort studies were identified. All studies were pooled to assess the relationship between total FBAs and cancer/adenoma of the large bowel, however, no association was seen (WMD 0.61mg/g freeze-dried feces; 95% CI: -0.35-1.57). Significantly increased concentration of chenodeoxycholic acid (CDCA) was seen while pooling to assess the relationship between CDCA and cancer/adenoma of the large bowel (WMD 0.13 mg/g freeze-dried feces; 95% CI: 0.01-0.25), especially for colorectal cancer (WMD 0.28mg/g freeze-dried feces; 95% CI: 0.10-0.46). However, no significant differences in deoxycholic acid (DCA), lithocholic acid (LCA), and primary and secondary bile acids, were seen between patients with cancer and patients with matched controls regardless of fixed and random effects models. Conclusion: CDCA might play a role in the etiology of colorectal cancer.
Jia Chen,Jianhua Shao,Chunchao Zhao,Jie Shen,Ziling Dong,Wenyan Liu,Min Zhao,Judi Fan 대한약학회 2018 Archives of Pharmacal Research Vol.41 No.6
Three new neolignans, fordianoles A-C (1–3),characterized as (7S,8R)-4-hydroxy-3,30,50-trimethoxy-80,90-dinor-8,40-oxyneolignan-7,70,9-triol, (7R,8R)-4-hydroxy-3,30,50-trimethoxy-80,90-dinor-8,40-oxyneolignan-7,70,9-triol, and (7R,8R)-4-hydroxy-3,30,50-trimethoxy-8,40-oxyneolignan-7,9,90-triol-70-one, together with an unusual c-lactone,3-(3,4-dihydroxyphenyl)-4-pentanolide (4), andtwenty-five known compounds (5–29) were isolated fromthe aerial parts of Viburnum fordiae Hance. Their structuresincluding absolute configurations were determined byspectroscopic and chemical methods. Among them, compounds6, 7, 11–15, 17–28 were isolated from the Viburnumgenus for the first time. The anti-inflammatory and antioxidantactivities of all compounds were evaluated in vitro. Compounds 15, 19, 20 and 29 showed significant inhibitoryactivity on NO production in RAW264.7 cells stimulated byLPS with IC50 values ranging from 8.60 to 13.92 lM. Meanwhile, compounds 1–4, 15, 19, 20, 22, 23, 25, 26 and29 exhibited varying antioxidant activities through DPPH,ABTS free radical scavenging and FRAP assays.