• Title/Summary/Keyword: 압축 피로

Search Result 243, Processing Time 0.017 seconds

Application of Ultrasonic Nano Crystal Surface Modification into Nitinol Stent Wire to Improve Mechanical Characteristics (나이티놀 스텐트 와이어의 기계적 특성 향상을 위한 초음파 나노표면 개질 처리에 대한 연구)

  • Kim, Sang-Ho;Suh, Tae-Suk;Lee, Chang-Soon;Park, In-Gyu;Cho, In-Sik;Pyoun, Young-Shik;Kim, Seong-Hyeon
    • Progress in Medical Physics
    • /
    • v.20 no.2
    • /
    • pp.80-87
    • /
    • 2009
  • Phase transformation, superelastic characteristics and variation of surface residual stress were studied for Nitinol shape memory alloy through application of UNSM technology, and life extension methods of stent were also studied by using elastic resilience and corrosion resistance. Nitinol wire of ${\phi}1.778$ mm showed similar surface roughness before and after UNSM treatment, but drawing traces and micro defects were all removed by UNSM treatment. It also changed the surface residual stress from tensile to compressive values, and XRD result showed less intensive austenite peak and clear martensite and additional R-phase peaks after UNSM treatment. Fatigue resistance could be greatly improved through removal of surface defects and rearrangement of surface residual stress from tensile to compressive state, and development of surface modification system to improve not only bio-compatability but also resistance to corrosion and wear will make it possible to develop vascular stent which can be used for circulating system diseases which run first cause of death of recent Koreans.

  • PDF

Development and Content Characteristics of Cartoons in the 1910s: focusing on cartoons published in Maeilsinbo (1910년대 만화의 전개와 내용적 특질: 『매일신보』 게재 만화를 중심으로)

  • Seo, Eun-Young
    • Cartoon and Animation Studies
    • /
    • s.30
    • /
    • pp.139-168
    • /
    • 2013
  • This article aims to explain the significance and value of cartoons in the 1910s which were largely passed unnoticed in the preceding cartoon studies by scrutinizing cartoons published in Maeilsinbo in the 1910s. Until now, Korean cartoons in the 1910s has been neglected just because it were published in Maeilsinbo. However, this writing analyzed cartoons in this period on the base of the fact that the cartoons in the 1910s printed in Maeilsinbo diversified the horizon of the Korean cartoon. Cartoons in Maeilsinbo functioned as a bridge connecting cartoons published in Daehanminbo in 1909 reputed as a root of Korean cartoon and 1920s, the time when satirical cartoons and comics started being printed in newspapers. The characteristics of Maeilsinbo as a bulletin of government general and periodical characteristics that the agent of popular culture begun to move reside as multi layers in the cartoons in the 1910s. In this article, the process and the development of how cartoons published in Maeilsinbo. As pleasure became important in everyday life in Korea, cartoons were able to earn a portion in the newspaper. In the beginning, modern cartoon style seemed vague, but as time goes by, its own style gradually settled. Cartoons in this period were not fixed in specific section but various kinds of cartoons were developed during the time since works of Korean as well as Japanese cartoonists and illustrators were published. Among them, representative cartoons in Maeilsinbo were analyzed in this article under three categories: first, cartoons represented 'Choseon-ness' through scenes of daily life and customs concurrently contained a view of anti-civilization/enlightenment; second, cartoons represented the accumulation of wealth as valid from the view point of public interest; last, cartoons divided Koreans who suffered from hardships of life in Kyungsung and Japanese in Jingogae in order to divide space. In conclusion, Maeilsinbo disciplined the colonized, Koreans, and exposed the discourse of the colonial power via cartoon.

Image Watermarking for Copyright Protection of Images on Shopping Mall (쇼핑몰 이미지 저작권보호를 위한 영상 워터마킹)

  • Bae, Kyoung-Yul
    • Journal of Intelligence and Information Systems
    • /
    • v.19 no.4
    • /
    • pp.147-157
    • /
    • 2013
  • With the advent of the digital environment that can be accessed anytime, anywhere with the introduction of high-speed network, the free distribution and use of digital content were made possible. Ironically this environment is raising a variety of copyright infringement, and product images used in the online shopping mall are pirated frequently. There are many controversial issues whether shopping mall images are creative works or not. According to Supreme Court's decision in 2001, to ad pictures taken with ham products is simply a clone of the appearance of objects to deliver nothing but the decision was not only creative expression. But for the photographer's losses recognized in the advertising photo shoot takes the typical cost was estimated damages. According to Seoul District Court precedents in 2003, if there are the photographer's personality and creativity in the selection of the subject, the composition of the set, the direction and amount of light control, set the angle of the camera, shutter speed, shutter chance, other shooting methods for capturing, developing and printing process, the works should be protected by copyright law by the Court's sentence. In order to receive copyright protection of the shopping mall images by the law, it is simply not to convey the status of the product, the photographer's personality and creativity can be recognized that it requires effort. Accordingly, the cost of making the mall image increases, and the necessity for copyright protection becomes higher. The product images of the online shopping mall have a very unique configuration unlike the general pictures such as portraits and landscape photos and, therefore, the general image watermarking technique can not satisfy the requirements of the image watermarking. Because background of product images commonly used in shopping malls is white or black, or gray scale (gradient) color, it is difficult to utilize the space to embed a watermark and the area is very sensitive even a slight change. In this paper, the characteristics of images used in shopping malls are analyzed and a watermarking technology which is suitable to the shopping mall images is proposed. The proposed image watermarking technology divide a product image into smaller blocks, and the corresponding blocks are transformed by DCT (Discrete Cosine Transform), and then the watermark information was inserted into images using quantization of DCT coefficients. Because uniform treatment of the DCT coefficients for quantization cause visual blocking artifacts, the proposed algorithm used weighted mask which quantizes finely the coefficients located block boundaries and coarsely the coefficients located center area of the block. This mask improves subjective visual quality as well as the objective quality of the images. In addition, in order to improve the safety of the algorithm, the blocks which is embedded the watermark are randomly selected and the turbo code is used to reduce the BER when extracting the watermark. The PSNR(Peak Signal to Noise Ratio) of the shopping mall image watermarked by the proposed algorithm is 40.7~48.5[dB] and BER(Bit Error Rate) after JPEG with QF = 70 is 0. This means the watermarked image is high quality and the algorithm is robust to JPEG compression that is used generally at the online shopping malls. Also, for 40% change in size and 40 degrees of rotation, the BER is 0. In general, the shopping malls are used compressed images with QF which is higher than 90. Because the pirated image is used to replicate from original image, the proposed algorithm can identify the copyright infringement in the most cases. As shown the experimental results, the proposed algorithm is suitable to the shopping mall images with simple background. However, the future study should be carried out to enhance the robustness of the proposed algorithm because the robustness loss is occurred after mask process.