With smaller pits and lands in multi-level optical disks using signal waveform modulation than those in DVD disks, the ISI and nonlinear attenuation of the read-out signal become more serious. One ordinary way is using an equalizer at sample rate 1/T, we proposed one method of designing the equalizer in fixed sample rate with digital interpolation. According to the analysis of the multi-level optical disk channel, we get the target frequency-response cure and implement it with seven order FIR filter. From the result of the read out experiment with multi-level optical disk, the clock of the RF signal could be recovered with the proposed equalizer.
A new kind of multi-level recordable disc is presented in this paper. By improving the recording control signal in DVD-R/RW burning process, a Multi-level disc with signal waveform modulation can be achieved. The multi-level recording method increases the recording density but also the channel noise. The optimally designed partial response maximum likelihood (PRML) equalizer is effective in recovering channel symbol, and the original error rate reach 10E-4. This kind of multi-level method can be used for the purpose such as increasing the capacity of disc, hiding data and burning disc identification information etc.
Nowadays, OMNERC research group is going to advance the capacity to 15GB by reducing the 3T pit length and
increasing the level of long pit based on the signal waveform modulation (SWM) ML recording technology. In order to
prove this method is realizable, this paper proposes the restriction points of consideration to reduce the minimum pit
length which influence the basic specification design of multi-level disk and the difficulty of the following signal
processing. Firstly the restriction of optical pick-up resolution is considered. Secondly, the restriction caused by read-out
channel is discussed in the paper. At the same time as write strategy has its limit based on the previous research, this
paper finally discuss the influence caused by minimize shortest pit length for level design of long length pit.
Storage technology has enjoyed considerable growth since the first disk drive was introduced nearly 50 years ago. Various storage devices with large volume and high performance are emerging and they carry the important information for our social life. How to make the devices more broadly and effectively used and make the information more available is a problem for today. IP-based Storage provides such a cheap interface for storage devices under the rapid development of network technology. This paper answers what is network storage relative to traditional storage and then puts emphasis on two typical IP-based storage technologies NAS and iSCSI. The article evaluates the performance of NAS and iSCSI by measuring and analyzing file-level access performance and block-level access performance. Our test results show that iSCSI provides higher performance then using NFS protocol in Linux or SMB protocol in Windows (NAS scheme). The last part of the paper gives characteristic and trade-off of several IP-based storage system architectures.
This paper presents a fractal-based method for natural scene image segmentation. The main goal is to find artifact objects from complex natural scene. We propose a set of fractal measurements in order to acquire various aspects of roughness of each part of an image. The performance of the data fitting in the box-dimension estimation is analyzed and an improved algorithm is proposed. Experiments prove that the proposed approach is suitable for texture segmentation and artifact object finding in natural environment images.