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The traditional hard disk drive (HDD) is often a bottleneck in the overall performance of modern computer systems. With the development of solid state drives (SSD) based on flash memory, new possibilities are available to improve secondary storage performance. In this work, we propose a new hybrid SSD–HDD storage system and a selection of algorithms designed to assign pages across an HDD and an SSD...
This paper presents a combination approach to robust speech recognition by using two-stage model-based feature compensation. Gaussian mixture model (GMM)-based and hidden Markov model (HMM)-based compensation approaches are combined together and conducted sequentially in the multiple-decoding recognition system. The clean speech is firstly modeled as a GMM in the initial pass, and then modeled as...
Disk idle behavior has a significant impact on the energy efficiency of disk storage systems. For example, accurately predicting or extending the idle length experienced by disks can generate more potential opportunities to save energy. This paper employs a trace driven simulation to evaluate the impacts of different disk schedulers and queue length thresholds on the disk idle behavior. Experimental...
In this paper we will discuss different realizations for an efficient interval arithmetic implementation using expression templates and template meta programming in C++. We will improve the handling of the rounding mode switches using expression templates and show how the constructed expression trees can be combined with other features like automatic differentiation. For a further improvement of the...
The paper considers systems of linear interval equations, i.e., linear systems where the coefficients of the matrix and the right hand side vary between given bounds. We focus on symmetric matrices and consider direct methods for the enclosure of the solution set of such a system. One of these methods is the interval Cholesky method, which is obtained from the ordinary Cholesky decomposition by replacing...
This paper describes a new algorithm for computing verified bounds on the distance between two arbitrary fat implicit objects. The algorithm dissects the objects into axis-aligned boxes by constructing an adaptive hierarchical decomposition during runtime. Actual distance computation is performed on the cubes independently of the original object’s complexity. As the whole decomposition process and...
We present numerically verified a posteriori estimates of the norms of inverse operators for linear parabolic differential equations. In case that the corresponding elliptic operator is not coercive, existing methods for a priori estimates of the inverse operators are not accurate and, usually, exponentially increase in time variable. We propose a new technique for obtaining the estimates of the inverse...
In interval arithmetics, special care has been brought to the definition of interval extension functions that compute narrow interval images. In particular, when a function f is monotonic w.r.t. a variable in a given domain, it is well-known that the monotonicity-based interval extension of f computes a sharper image than the natural interval extension does. This paper presents a so-called “occurrence...
In this paper, we propose an algorithm for constrained global optimization of mixed-integer nonlinear programming (MINLP) problems. The proposed algorithm uses the Bernstein polynomial form in a branch-and-bound framework. Ingredients such as continuous relaxation, branching for integer decision variables, and fathoming for each subproblem in the branch-and-bound tree are used. The performance of...
In many control applications, we are interested in accurate trajectory tracking. This is especially true for cases in which exact analytic solutions are not available because initial states are not consistent with the desired state or output trajectories or because parameters are significantly uncertain. In these cases, control strategies can be derived on the basis of a verified sensitivity analysis...
Fault tree analysis is a method to determine the likelihood of a system attaining an undesirable state based on the information about its lower level parts. However, conventional approaches cannot process imprecise or incomplete data. There are a number of ways to solve this problem. In this paper, we will consider the one that is based on the Dempster–Shafer theory. The major advantage of the techniques...
Obtaining verified numerical solutions to initial value problems (IVPs) for ordinary differential equations (ODEs) is important in many application areas (e.g. biomechanics or automatic control). During the last decades, a number of solvers have been developed for this purpose. However, they are rarely used by industry engineers. One reason for this is the lack of information about what tool with...
This survey aims at giving both a dynamical and computer arithmetic-oriented presentation of several classical numeration systems, by focusing on the discrete dynamical systems that underly them: this provides simple algorithmic generation processes, information on the statistics of digits, on the mean behavior, and also on periodic expansions (whose study is motivated, among other things, by finite...
As a new feature, C-XSC provides so-called wrapper classes to some external arbitrary precision real and interval packages. Operator and function name overloading is used to give the user easy access to the arithmetic operations and mathematical functions provided by the underlying Ansi C packages. We will discuss briefly so-called staggered precision arithmetics based on exact scalar products. Such...
In contrast to integration, the differentiation of a function is an ill-conditioned process, if only an oracle is available for its pointwise evaluation. That is, unrelated small variations in the value of the composite function are allowed at nearly identical arguments. In contrast, we show here that, if the function is defined by an evaluation procedure as a composition of arithmetic operations...
In this paper, we consider the resolution of constraint satisfaction problems in the case where the variables of the problem are subsets of $${\mathbb{R}^{n}}$$ . In order to use a constraint propagation approach, we introduce set intervals (named i-sets), which are sets of subsets of $${\mathbb{R}^{n}}$$ with a lower bound and an upper bound with respect to the inclusion. Then, we propose...
We often need to deal with information that contains both interval and probabilistic uncertainties. P-boxes and Dempster–Shafer structures are models that unify both kind of information, but they suffer from the main defect of intervals, the wrapping effect. We present here a new arithmetic that mixes, in a guaranteed manner, interval uncertainty with probabilities, while using some information about...
Interval arithmetic, as it is standardized by the IEEE working group P1788 can be implemented by using floating point arithmetic units with directed rounding modes. The easiest way to represent an interval is by its two bounds. Simple formulas for the arithmetic operations can be applied. Our goal is to perform interval operations as fast as their floating point counterparts. Hence, we provide at...
For nonlinear systems, feedback control strategies have to be parameterized in such a way that they guarantee asymptotic stability in a certain neighborhood of desired operating points or desired trajectories. Due to not exactly known initial conditions, parameter uncertainties, and measurement errors characterizing dynamic system models in real applications, interval techniques are taken into consideration...
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