中国科学院机构知识库网格
Chinese Academy of Sciences Institutional Repositories Grid
机构
采集方式
内容类型
发表日期
学科主题
筛选

浏览/检索结果: 共9条,第1-9条 帮助

条数/页: 排序方式:
Y-Mat: an improved hybrid finite-discrete element code for addressing geotechnical and geological engineering problems 期刊论文  OAI收割
ENGINEERING COMPUTATIONS, 2022, 页码: 22
作者:  
Liu, Gang;  Ma, Fengshan;  Zhang, Maosheng;  Guo, Jie;  Jia, Jun
  |  收藏  |  浏览/下载:38/0  |  提交时间:2022/07/05
Application of Coded Excitation Signals for Measurement of Rock Ultrasonic Wave Velocity 期刊论文  OAI收割
PURE AND APPLIED GEOPHYSICS, 2020, 卷号: 177, 期号: 1, 页码: 487-496
作者:  
Wu, He-Zhen;  Zhu, Wei;  He, Tai-Ming;  Liu, Zheng-Yi;  Lan, Xiao-Wen
  |  收藏  |  浏览/下载:68/0  |  提交时间:2020/05/18
A reconfigurable computing architecture for 5G communication 期刊论文  OAI收割
Journal of Central South University, 2019, 期号: 0, 页码: 0
作者:  
GUO Yang;  LIU Zi-Jun;  YANG Lei;  LI Huan;  WANG Dong-Lin
  |  收藏  |  浏览/下载:93/0  |  提交时间:2019/07/11
Numerical Investigation of Mineral Grain Shape Effects on Strength and Fracture Behaviors of Rock Material 期刊论文  OAI收割
APPLIED SCIENCES-BASEL, 2019, 卷号: 9, 期号: 14, 页码: 14
作者:  
Han, Zhenhua;  Zhang, Luqing;  Zhou, Jian
  |  收藏  |  浏览/下载:121/0  |  提交时间:2019/10/14
SOPC处理器的程序压缩与解压研究 学位论文  OAI收割
工学博士, 中国科学院自动化研究所: 中国科学院大学, 2015
作者:  
涂吉
收藏  |  浏览/下载:65/0  |  提交时间:2015/09/02
Compression of hyper-spectral images based on quadtree partitioning (EI CONFERENCE) 会议论文  OAI收割
2009 2nd IEEE International Conference on Computer Science and Information Technology, ICCSIT 2009, August 8, 2009 - August 11, 2009, Beijing, China
作者:  
Zhang W.;  Zhang W.
收藏  |  浏览/下载:42/0  |  提交时间:2013/03/25
The compression and storage method of the same kind of medical images-DPCM (EI CONFERENCE) 会议论文  OAI收割
4th International Conference on Photonics and Imaging in Biology and Medicine, September 3, 2005 - September 6, 2005, Tianjin, China
作者:  
Liu H.;  Liu H.;  Liu H.
收藏  |  浏览/下载:16/0  |  提交时间:2013/03/25
Medical imaging has started to take advantage of digital technology  opening the way for advanced medical imaging and teleradiology. Medical images  however  require large amounts of memory. At over 1 million bytes per image  a typical hospital needs a staggering amount of memory storage (over one trillion bytes per year)  and transmitting an image over a network (even the promised superhighway) could take minutes - too slow for interactive teleradiology. This calls for image compression to reduce significantly the amount of data needed to represent an image. Several compression techniques with different compression ratio have been developed. However  the lossless techniques  which allow for perfect reconstruction of the original images  yield modest compression ratio  while the techniques that yield higher compression ratio are lossy  that is  the original image is reconstructed only approximately Medical imaging poses the great challenge of having compression algorithms that are lossless (for diagnostic and legal reasons) and yet have high compression ratio for reduced storage and transmission time. To meet this challenge  we are developing and studying some compression schemes  which are either strictly lossless or diagnostically lossless  taking advantage of the peculiarities of medical images and of the medical practice. In order to increase the Signal to-Noise Ratio (SNR) by exploitation of correlations within the source signal  a method of combining differential pulse code modulation (DPCM) is presented.  
Lossless wavelet compression on medical image (EI CONFERENCE) 会议论文  OAI收割
4th International Conference on Photonics and Imaging in Biology and Medicine, September 3, 2005 - September 6, 2005, Tianjin, China
作者:  
Liu H.;  Liu H.;  Liu H.
收藏  |  浏览/下载:41/0  |  提交时间:2013/03/25
An increasing number of medical imagery is created directly in digital form. Such as Clinical image Archiving and Communication Systems (PACS). as well as telemedicine networks require the storage and transmission of this huge amount of medical image data. Efficient compression of these data is crucial. Several lossless and lossy techniques for the compression of the data have been proposed. Lossless techniques allow exact reconstruction of the original imagery while lossy techniques aim to achieve high compression ratios by allowing some acceptable degradation in the image. Lossless compression does not degrade the image  thus facilitating accurate diagnosis  of course at the expense of higher bit rates  i.e. lower compression ratios. Various methods both for lossy (irreversible) and lossless (reversible) image compression are proposed in the literature. The recent advances in the lossy compression techniques include different methods such as vector quantization  wavelet coding  neural networks  and fractal coding. Although these methods can achieve high compression ratios (of the order 50:1  or even more)  they do not allow reconstructing exactly the original version of the input data. Lossless compression techniques permit the perfect reconstruction of the original image  but the achievable compression ratios are only of the order 2:1  up to 4:1. In our paper  we use a kind of lifting scheme to generate truly loss-less non-linear integer-to-integer wavelet transforms. At the same time  we exploit the coding algorithm producing an embedded code has the property that the bits in the bit stream are generated in order of importance  so that all the low rate codes are included at the beginning of the bit stream. Typically  the encoding process stops when the target bit rate is met. Similarly  the decoder can interrupt the decoding process at any point in the bil stream  and still reconstruct the image. Therefore  a compression scheme generating an embedded code can start sending over the network the coarser version of the image first  and continues with the progressive transmission of the refinement details. Experimental results show that our method can get a perfect performance in compression ratio and reconstructive image.  
Wavelet packet and neural network basis medical image compression (EI CONFERENCE) 会议论文  OAI收割
4th International Conference on Photonics and Imaging in Biology and Medicine, September 3, 2005 - September 6, 2005, Tianjin, China
Zhao X.; Wei J.; Zhai L.
收藏  |  浏览/下载:20/0  |  提交时间:2013/03/25
It is difficult to get high compression ratio and good reconstructed image by conventional methods  we give a new method of compression on medical image. It is to decompose and reconstruct the medical image by wavelet packet. Before the construction the image  use neural network in place of other coding method to code the coefficients in the wavelet packet domain. By using the Kohonen's neural network algorithm  not only for its vector quantization feature  but also for its topological property. This property allows an increase of about 80% for the compression rate. Compared to the JPEG standard  this compression scheme shows better performances (in terms of PSNR) for compression rates higher than 30. This method can get big compression ratio and perfect PSNR. Results show that the image can be compressed greatly and the original image can be recovered well. In addition  the approach can be realized easily by hardware.