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Fast Scene Change Detection Algorithm
Khvan, Dmitriy,Ng, Teck Sheng,Jeong, Jechang 한국방송·미디어공학회 2012 한국방송공학회 학술발표대회 논문집 Vol.2012 No.11
In this paper, we propose a new fast algorithm for effective scene change detection. The proposed algorithm exploits Otsu threshold matching technique, which was proposed earlier. In this method, the current and the reference frames are divided into square blocks of particular size. After doing so, the pixel histogram of each block is generated. According to Otsu method, every histogram distribution is assumed to be bimodal, i.e. pixel distribution can be divided into two groups, based on within-group variance value. The pixel value that minimizes the within-group variance is said to be Otsu threshold. After Otsu threshold is found, the same procedure is performed at the reference frame. If the difference between Otsu threshold of a block in the current frame and co-located block in the reference frame is larger than predefined threshold, then a scene change between those two blocks is detected.
( Khvan Ekaterina ),( Yemi Kim ),( Ji Youn Kim ),( Myung Rae Kim ),( Sung O Kim ),( Sun Jong Kim ) 한국조직공학·재생의학회 2012 조직공학과 재생의학 Vol.9 No.5
The objective of this study was to evaluate the feasibility of a new xenograft material Ti-Oss (Chiyewon, Guri, Korea) by investigating the degree of new bone formation compared with that of other commonly used xenografts Bio-Oss(R)(Geistlich Pharma AG, Wolhusen, Switzerland) and OCS-B(R)(NIBEC, Seoul, Korea). Forty rats were used in the study. The animals were randomly allocated into four groups of 10 animals each. The Group 1`s calvarial defect was untreated, Group 2`s defect was filled with Bio-Oss(R)(Geistlich Pharma AG), Group 3`s defect was filled with OCS-B(R)(NIBEC), and Group 4`s defect was filled with Ti-Oss(R)(Chiyewon). The animals were sacrificed at 2 (n=5) and 8 (n=5) weeks for histomorphometric analysis. The histomorphometric analysis showed the statistically significant difference between the groups with a mean bone formation of 0.35±0.10 mm (8.75%) for Bio-Oss(R) group, 0.19±0.04 mm (4.75%) for OCS-B(R) group, 0.26±0.04 mm (6.5%) for Ti-Oss(R) group at 2 week healing period. At 8 weeks, a mean bone formation of 1.93±0.18 mm (48.25%) for Bio-Oss(R) group, 1.12±0.11 mm (28%) for OCS-B(R) group, 1.50±0.28 mm (37.5%) for Ti-Oss(R) group showed the statistically significant difference (p < 0.05). Within the limits of present study, it was concluded that the newly investigated xenograft, Ti-Oss(R), revealed biocompatibility and effectiveness in bone formation. Ti-Oss(R) could be proposed as a potential material for filling osseous defects. Further clinical trials of the new bovine xenograft Ti-Oss(R) are needed for an understanding its relevance in dentistry.
Fabrication of Pre-Exfoliated Clay Masterbatch via Exfoliation-Adsorption of Polystyrene Nanobeads
Khvan, Svetlana,Kim, Jun-Kyung,Lee, Sang-Soo The Polymer Society of Korea 2007 Macromolecular Research Vol.15 No.1
The approach studied in the present work produced an exfoliated state of clay layers via confinement of the charged nano-sized polystyrene (PS) beads within the gallery of swollen pristine clay. It was demonstrated that adsorption of the polymer nanobeads dramatically promotes expansion of the clay gallery. A comparative study of incorporation was conducted by employing organo-modified clay along with two different colloid polymer systems: electrostatically stabilized PS nanobeads and cationic monomer-grafted PS nanobeads. The mechanism of adsorption of the monomer-grafted polymer beads onto clay via cationic exchange between the alkyl ammonium group of the polymer nanobeads and the interlayer sodium cation of the layered silicate was verified by using several techniques. As distinct from the polymer nanobeads formed using conventional miniemulsion polymerization method, competitive adsorption of stabilizing surfactant molecules was be prevented by grafting the surface functional groups into the polymer chain, thereby supporting the observed effective adsorption of the polymer beads. The presence of surface functional groups that support the establishment of strong polymer-clay interactions was suggested to improve the compatibility of the clay with the polymer matrix and eventually play a crucial role in the performance of the final nanocomposites.
Hybrid Deinterlacing Algorithm with Motion Vector Smoothing
Khvan, Dmitriy,Jeon, Gwanggil,Jeong, Jechang 한국방송·미디어공학회 2012 한국방송공학회 학술발표대회 논문집 Vol.2012 No.7
In this paper we propose a new deinterlacing method with block classification and motion vector smoothing. The proposed method classifies a block, then depending on the region it belongs to, the motion estimation or line averaging is applied. To classify a block its variance is calculated. Then, for those blocks that belong to simple non-texture region the line averaging is done while motion estimation is applied to complex region. The motion vector field is smoothed using median filter what yields more accurate interpolation. In the experiments for the subjective evaluation, the proposed method bas shown satisfying results in terms of computation time consumption and peak signal-to-noise ratio. Due to the simplicity of the algorithm computation time was drastically decreased.
( Marina Khvan ),( Nazym Nigmatullina ),( Saltanat Rakhimzhanova ),( Samat Issakov ),( Venera Altynova ) 대한간학회 2020 춘·추계 학술대회 (KASL) Vol.2020 No.1
Introduction: Hepatitis C virus (HCV) infection is an important co-morbidity in patients after kidney transplantation (KT) affecting patient and graft survival. In the era of Direct Acting Antiviral (DAA) drugs the current standards of management strongly suggest to treat HCV positive patient with end-stage renal disease (ESRD) before KT. However, in the conditions where this treatment is not available, KT remains the only lifesaving option for children with ESRD who is not able to sustain on dialysis any longer. Aim: Currently, there is limited data available about outcomes of pediatric patients with HCV after kidney transplantation. We studied the prevalence, clinical profile and outcome of HCV infection in KT pediatric recipients (KTPR) in Kazakhstan for the first time after the launching the National Pediatric KT Program in 2012. Methods: We studied pediatric patients who underwent KT from January 2012 to December 2018 at the Department of Nephrology, Dialysis and Transplantation, National Research Center of Mother and Child Health, University Medical Center, Nur-Sultan. HCV infection was defined as a positive anti-HCV antibody and/or HCV RNA PCR positivity. Control group included KTPRs with no evidence of HCV or hepatitis B virus (HBV) infection. Results: A total of 73 KTPRs were included. The mean age was 10.6 ± 4.5 years, male:female ratio was 1:1 and mean duration of post-transplant follow-up was 32 months. 9 patients (12%) had evidence of HCV infection. All HCV-positive patients underwent KT before DAAs were available in the country. Among them 4 patients were treated with interferon before KT, 4 patients had HCV infection by the time of KT and 1 patient developed de-novo HCV infection after KT. Although there was no statistical significant difference in patient survival (logrank P=0.82) and graft survival (log-rank P=0.416) between HCV-positive group and controls, the only death in HCV group was registered in the patient who had de-novo HCV infection after KT. 2 patients who were treated from HCV infection before KT lost their kidney grafts and returned on dialysis. Among 4 patients with persistent HCV infection by the time of KT, 2 were successfully treated with DAAs 5 years after KT without any side effects or worsening of graft function. 2 KTPRs still have chronic HCV infection Stage 0 - 1 with low viral load, normal liver function tests and normal kidney graft function over the 6 years after KT. Conclusions: In our cohort HCV-positive KTPRs did not have any difference in patient and graft survival comparing to KTPRs without HCV infection. The worst outcome had patient with de-novo developed HCV infection after KT. HCV treatment with DAA after KT was successful without deterioration of kidney graft function. Limitation: low number of HCV-positive KTPRs.
Large scale vertical implantation of crystalline titania nanotube arrays
Svetlana V. Khvan,이상수,홍성철,김준경 한국공업화학회 2011 Journal of Industrial and Engineering Chemistry Vol.17 No.6
We present simple method to fabricate large scale TiO2 nanotube arrays of a few tens micrometers length perpendicularly implanted on transparent electroconducting glass substrate. The thickness and morphology of the titania nanotube arrays layer can be easily tuned, enabling designing the optimal architecture of the nanostructured titania film for diverse applications including dyesensitized solar cell.