No abstract

No abstract

In this paper, we present a flexible simulation environment for the performance evaluation of flash-aware algorithms, which is called Flash-DBSim. The main purpose of Flash-DBSim is to provide a configurable virtual flash disk for upper systems, such as file system and DBMS, so that the algorithms in those systems can be easily evaluated on different types of flash disks. Moreover, it also offers a prototyping environment for those algorithms inside flash disk, e.g. the algorithms for garbage collection or wearleveling. After an overview of the general features of FlashDBSim, we discuss the architecture of Flash-DBSim. And finally, a case study of Flash-DBSim's demonstration is presented.

The traditional ICP algorithm is a de facto standard approach for range image registration. While it assumes that one data set is a subset of another, this assumption is often violated in practice. As a result, a number of algorithms have been developed to first eliminate false matches due to occlusion, appearance and disappearance of points and then estimate the camera motion parameters in the least squares sense. Instead of eliminating outliers in the process of image registration, we in this paper use the generalised entropy to estimate the probability of correspondences established using the traditional closest point criterion, leading camera motion parameters to be estimated in the weighted least squares sense. For more accurate registration results, we also learn from the probability of correspondences estimated in the past. Since one point in one data set can only correspond to a single point in another, the two way constraint is also imposed. Finally the camera motion parameters are optimized using the powerful mean field annealing scheme. A comparative study based on real images has shown that the proposed algorithm produces promising automatic range image registration results.

Flash memory is becoming an attractive alternative to traditional hard disks, because of its small-size, shockresistant, power-economic, and non-volatile natures. In order to utilize the special I/O properties of flash disks, a lot of new database technologies have been proposed. However, it comes to be a critical problem that researchers are difficult to evaluate their algorithms on current DBMS. People usually have to design and implement different simulating tools to verify the new algorithms on flash disks, and this brings much hard and redundant work. In this paper, we aim at providing a common simulating tool for the evaluation of new algorithms on flash disks. The new tool, named Flash-DBSim, is designed to be reusable and flexible for other researchers to reduce their redundant work. After a brief introduction on the architecture of Flash-DBSim, we present the implemental details of Flash-DBSim. Then, we give a sample use of Flash-DBSim, which aims at evaluating the B+ tree and linear hash index on flash disks. The results show that Flash-DBSim is easy to reconfigure to evaluate the I/O performance of algorithms on flash disks.