This paper introduces a new memory scheduling policy called LAMS, which is inspired by a recently proposed memory architecture and targets for future high capacity memory systems. As memory capacity increases, the bit-lines connected to memory row buffers become much longer, dramatically lengthening memory access latency, due to increased parasitic capacitance. Recent study has proposed to partition long bit-lines into near and far (relative to the row buffer) segments via inserting isolation transistors such that access to near segment can be accomplished much faster, while access to far segment remains nearly the same. However, how to effectively leverage the new memory architecture still remains unexplored. We suggest to take advantage of this new memory architecture via performing latency-aware memory scheduling for pending requests to explore their performance potentials. In this scheduling policy, each memory request is classified to one of the following three categories, row-buffer hit, near-buffer, and far-buffer. Based on the classification, it issues requests in the order of row-buffer hit → near-buffer → far-buffer. In doing so, it avoids long-latency requests blocking short-latency memory requests, reducing total memory queuing time in the memory controller and improving overall memory performance. Our evaluation results on a simulated memory system show that comparing with the commonly used FR-FCFS scheduler, our LAMS improves performance and energy efficiency by up to 20.6% and 34%, respectively. Even comparing with the four competitive schedulers chosen from memory scheduling champion (MSC), LAMS still improves performance and energy efficiency by up to 6.1% and 23.4%, respectively.

Heath information exchange (HIE) is the next step of health informatics development in China. Conformed to the administration feature, the design of HIE platform adopts a centralized architecture, which has to accommodate large amount of health information and support various types of query and data retrieval. Cloud computing is a suitable for the technology requirements of centralized design. In this paper, we proposed a medical information platform based on Hadoop, named after Medoop. The present Medoop utilizes HDFS to store the merged CDA documents efficiently, organize the feature information in CDA documents according to frequent business queries, and compute statistic distributedly in MapReduce paradigm. The objective of Medoop is to construct a comprehensive platform for health information storage and exchange, utilizing the components in Hadoop ecosystem.

This paper presents a novel block I/O scheduler specifically for SSDs. The scheduler leverages the internal rich parallelism resulting from SSD's highly parallelized architecture. It speculatively divides the entire SSD space into different subregions and dispatches requests into those subregions in a round-robin fashion at the Linux kernel block layer. In the meanwhile, to reduce the severe read-write interference problem associated with SSDs, the scheduler only dispatches a batch of unidirectional requests to the disk driver for each subregion's scheduling opportunity. Furthermore, to take advantage of SSD'S better sequential performance over random patterns, the scheduler sorts the pending requests while they are awaiting in the dispatching queues as those HDD-oriented schedulers do. The experimental results with a variety of workloads have demonstrated that the new I/O scheduler not only improves the user-perceived performance, but also enhances the underlying SSD's lifetime via reducing the block erase operations during the running processes.

Flash-based SSDs are becoming increasingly popular in modern storage systems, especially in high-performance computing infrastructures. However, several inherent technical limitations still remain to prevent their widespread deployment. One of the critical concerns is their limited lifetime, which is directly relevant to the total writes experienced by SSDs. In this paper, we present a Content and semantics Aware File System (CSA-FS) which is able to reduce write traffic to SSDs. It employs deduplication and delta-encoding techniques to file system data blocks and semantic blocks, respectively. It is motivated by two important observations: (1) there exists a huge amount of content redundancy within primary storage systems, and (2) semantic blocks are visited much more frequently than data blocks, with each update bringing very minimal changes. By separately deduplicating redundant data blocks and delta-encoding similar semantic blocks, CSA-FS can significantly reduce the total write traffic to SSDs and greatly improve their lifetime correspondingly, at an acceptable cost of at most 7% performance degradation across a variety of workloads.

Common least significant bit (LSB) relevant steganography methods in speech frames often base on bits evaluation by certain speech quality evaluation criterion and together with some coding and embedding strategies to enhance imperceptibility and efficiency. However, some embedding capabilities and security strategy are neglected. This paper proposes a state-based steganography method which fully investigates speech frame features in order to expand embedding capabilities and enhance steganography security. In the proposed method, embedding capabilities are measured by available numbers of states relative to current frame parameters rather than information bits. And secret information embedding procedure is performed by the chosen states mapped operations. This is a basic fine-grained steganography solution which is useful for other algorithms based on it. The experimental results have demonstrated that statebased method outperforms traditional LSB substitution in overall performance and introduces limited latency, which meets the realtime requirement in covert communications.

This study presents a comprehensive empirical investigation on the interplay between actively-deployed file systems and an SSD. We test and analyze the performance of four widely used Linux file systems, which are ext2, ext3, XFS and Reiserfs, on an SSD with a range of different workloads. It is primarily intended to serve two purposes. One is that considering its widespread adoption trend, we are realistically motivated to have first-hand numbers of the actual performance of the emerging storage technology, especially in the contexts of daily deployment scenarios. The other goal is that we attempt to disclose the internal details behind the SSD's thin interface from a high-level perspective, totally different than those previous studies, which are typically micro-testonly. As a result of this study, we obtain several interesting and useful findings: (1) Generally, different file systems perform disparately on the SSD due to their various design principles, sometimes even with up to one order of magnitude of performance discrepancy. (2) File system format/mount options and workload characteristics have significant impacts on performance. (3) SSD would deliver optimal performance if used in a friendly manner. (4) Workloads, file systems and SSD interact in an intrinsically complicated way and in order to have optimal synergistic performance anticipation, users should seriously consider all of the three factors together, when setting up their SSD-based storage systems.

Time-traveling ability, which enables storage state to be reverted to any previous timepoints, is a highly desirable functionality in modern storage systems to ensure storage continuity. Continuous Data Protection (CDP) is a typical time-traveling implementation mechanism. CDP can guard well against software bugs, unintentional errors, malicious attacks, all of which are often beyond the capabilities of traditional periodical backup schemes. Broadly speaking, CDP can be implemented in two different ways, i.e., either integrate it seamlessly to the target file systems or more generally make it sit at the device block level. However, the state-of-the-art CDP implementations suffer from various limitations, e.g., huge implementation complexity, non-trivial performance interference. In this study, we introduce BVSSD, a new block level versioning system specifically designed for the emerging flash-based SSD. BVSSD realizes CDP functionality through positively and usefully exploiting the inherent idiosyncrasies of flash, which is the well-known "no-overwritten" property. Specifically, BVSSD simply keeps track of the SSD FTL metadata changes, which essentially represent the dynamics of the SSD storage state, and restores them to past timepoints to perform recoveries. Compared with existing block-level CDP schemes, BVSSD is much more light-weight, less performance-interfering, easier to realize, and more importantly, it requires no intrusive modifications to the upper file systems and applications. Our trace-driven simulation results with a number of different realistic enterprise-scale workload traces have shown that BVSSD only incurs marginal performance overheads, somewhere between 3% and 8% performance degradation, while with minimum additional RAM requirement, which is an acceptable price for the high reliability that BVSSD can provide. Furthermore, given most of the typcial SSDs deployment scenarios and their ever-increasing capacity trend, BVSSD is realistically poised to be feasible to be deployed in actual situations.

A novel semi-fragile watermarking scheme based on support vector machine (SVM) for image authentication is proposed This scheme first gives a definition of wavelet coefficient direction tree, then the relation model between the root node and its offspring nodes is established using SVM, and further watermark is embedded and extracted based on this relation model. In this scheme, a tempering information matrix and a local tempering appraising function (TAFL) are defined for image authentication. TAFLis calculated by a sliding widow and the maximal TAFL, namely TAFM, is used to distinguish the acceptable operations from the malicious tempering. In addition, the system has sound robustness to JPEG compression and good secure because not only the watermark is scrambled by a transformation, but also the binding relation among coefficients significantly discourages an adversary from performing the collage attack.

The Heihe River is located in the northwest of the country. The river which originates on the northern side of the Qilian Mountain, flows through the north of the Hexi corridor and disappears in the Badan Jiran Desert on the Ala-shan Plateau. The weather in this region is controlled by the continental climate and the Tibet Plateau climate. The Eji-na Oasis in the Heihe River’s downstream is generally considered by Chinese ecological scientists to be the main eco-barrier in northern China. Now, economical and ecological issues from these past decades are now urgently right in front of us. In this paper, combined with fieldwork, two Land-sat TM images (1988a and 2000a) and geography information system are used to interpret land use and land cover changes of the Heihe watershed. The results show that the changes have taken place in land use and land cover in the Heihe watershed since 1988. Based on the analysis of eco-environmental effects of each reach, this paper offers some strategies for ecological restoration of Heihe River Basin. Firstly, forest in the upper reaches should be protected to prevent further deforestation. To increase the upper reaches’ water conservation ability and to protect its ecological function, the number of livestock must be limited. In the middle reaches of the watershed, no more cropland should be exploited, agricultural structures should be adjusted to utilize the limited water resources and some industries that have high water need or high pollution outputs should be restricted or canceled. Combating desertification should be a matter for urgent attention. In the lower reaches of the watershed, where Eji-na Oasis locates, efficiency of irrigation should be increased, artificial oases should be developed, enhanced, and protected, and environmental restoration should have a high priority on the National Government Agenda Policy.

Qinghai Lake is situated in northeast of Qinghai-Tibet Plateau, where the Yellow river and the Yangtze River source regions are located. These regions are praised as "the resources bank of biological species" and "China's water tower". But now, Qinghai-Tibet Plateau is suffering from ongoing land desertification and Qinghai Lake area is the most severely place among these regions. Based on field investigation and land desertification classification, applied remote sensing image processing software system ARC/INFOR and ARCVIEW, and utilized a 1: 50,000 land-use map of this area, two phases Landsat TM/ETM remote sensing data obtained in 1986 and 2005 were compared in this paper. Studies show that ecological environment in Qinghai Lake area is in continued deterioration. Land desertification is developing rapidly and desertified land is expanding at an annual rate of 2.72%. Land desertification in this area have been caused by warming and drying climate, rat-caused damages and the damages from pest, unreasonable human activity such as irrational constructing of infrastructure, improper grassland management, etc. The eco-environmental deterioration has resulted in negative influence to local society and economy, such as sharply decreased livestock carrying capacity, lowered living standard, more and more ecological refugee, serious social problems, etc. Such critical problems urge the authors to search for approaches of ecological alleviation in the Qinghai Lake area. So the following countermeasures are put forward: to implement ecology emigrating project and set up ecological compensative mechanism; to carry out restoration of grassland eco-system by eliminating rat and pest-caused damages; to establish scientific research bases for developing and spreading new-high applicable technologies; to establish the management system so as to make reasonable use of the grassland.

The source regions of the Yangtze River are situated in the hinterland of Qinghai-Tibet Plateau of the roof of the world, with a typical continental alpine climate. Countless rivers and creeks originate in the source regions, so it is praised as "China's water tower". Because of the abundant biological species, the source regions are praised as "the resources bank of biological species". Based on land ecological classification and field investigation, we mainly used the remote sensing techniques to contrast and analyze two-phase Landsat TM/ETM remote sensing data in 1991 and 2005. Utilized the software system of ARC/INFO and ARCVIEW to process the digital graphic, and adopted the methods of the Landscape ecological patterns to analyze the characteristics of the spatial changes and dynamic transfers of grassland. Results show that the natural condition is harsh and the eco-environment is fragile. The environmental problems in the source regions have been caused by the global climate changes, human activities, and rat-caused damages, etc. The critical problems urge the authors to seek approaches of ecological alleviation in the source regions of the Yangtze River. The ultimate intention of this paper is to contribute to the sustainable utilization of the resources as well as sustainable development of economy in the source regions of the Yangtze River.

An image digital watermarking technique using support vector regression (SVR) is proposed and researched in this paper. Firstly, the method of embedding and extracting watermarking from digital image is given. Then, the influence of SVR-learning parameters on the watermarking performance is analyzed, and the ideal value range of SVR-learning parameters for different images is given respectively. Finally, the results are validated with other images. Experimental results show that this technique can obtain good watermarking performance as well as good learning performance when RBF kernel is adopted with its width a from 8 to 10, balanceable parameter C from 0.8 to 1, insensitive parameter s from 0.008 to 0.01 respectively.