检索结果-内蒙古大学图书馆

Complexity-scalable beat detection with MP3 audio bitstreams

computer MUSIC JOURNAL 2008年第1期32卷 71-87页

作者： Zhu, Jia Wang, Ye Natl Univ Singapore Dept Comp Sci Singapore 117543 Singapore

With the growing popularity of the MPEG-1 Audio Layer 3 (MP3) format, handheld devices such as personal digital assistants (PDAs) and mobile phones have become important entertainment platforms. Unlike conventional audio equipment, mobile devices are characterized by limited processing power, battery life, and memory, as well as other constraints. Therefore, music-processing tasks like beat detection must be implemented using low-complexity algorithms to cope with the constraints of these mobile devices.

关键词： computer music POPULAR music SOUND recordings AUDIOVISUAL materials computer algorithms ELECTRONIC apparatus & appliances

来源：评论

学校读者我要写书评

暂无评论

Multimodality and Global Optimization in Aerodynamic Design

引用

AIAA JOURNAL 2013年第6期51卷 1342-1354页

作者： Chernukhin, Oleg Zingg, David W. Univ Toronto Inst Aerosp Studies N York ON M3H 5T6 Canada

Two optimization algorithms are presented that are capable of finding a global optimum in a computationally efficient manner: a gradient-based multistart algorithm based on Sobol sampling and a hybrid optimizer combining a genetic algorithm with a gradient-based algorithm. The optimizers are used to investigate multimodality in aerodynamic-shape-optimization problems. The performance of each algorithm is tested on an analytical test function as well as several aerodynamic-shape-optimization problems in two and three dimensions. In each problem the primary objectives are to classify the problem according to the degree of multimodality and to identify the preferred optimization algorithm for the problem. The results show that multimodality should not always be assumed in aerodynamic-shape-optimization problems. Typical two-dimensional airfoil-optimization problems are unimodal. Three-dimensional shape-optimization problems may contain local optima. The number of local optima tends to increase with increasing geometric degrees of freedom and design space bounds. For problems with a modest number of local optima, which we term somewhat multimodal, the gradient-based multistart Sobol algorithm is the most efficient method.

关键词： AERODYNAMICS -- Research GLOBAL optimization RESEARCH MATHEMATICAL optimization computer algorithms COMBINATORIAL optimization

来源：评论

学校读者我要写书评

暂无评论

Exploring the limits of prefetching

引用

IBM JOURNAL OF RESEARCH AND DEVELOPMENT 2005年第1期49卷 127-144页

作者： Emma, PG Hartstein, A Puzak, TR Srinivasan, V IBM Corp Div Res Thomas J Watson Res Ctr Yorktown Hts NY 10598 USA

We formulate a new approach for evaluating a prefetching algorithm. We first carry out a profiling run of a program to identify all of the misses and corresponding locations in the program where prefetches for the misses can be initiated. We then systematically control the number of misses that are prefetched, the timeliness of these prefetches, and the number of umused prefetches. We validate the accuracy of our approach by comparing it to one based on a Markov prefetch algorithm. This allows us to measure the potential benefit that any application can receive from prefetching and to analyzed application behaviour under conditions that cannot be explored with any known prefetching algorithm. Next, we analyze a system parameter that is vital to prefetching performance, the line transfer interval, whish is the number of processor cycles required to transfer a cache line. This interval is determined by technology and bandwidth. We show that under ideal conditions, prefetching can remove nearly all of the stalls associated with cache misses. Unfortunately, real processor implementations are less than ideal. In particular, the trend in processor frequency is outrunning on-chip and off-chip bandwidths. Today, it is not uncommon for processor frequency to be three or four times bus frequency. Under these conditions, we show that nearly all of the performance benefits derived from prefetching are eroded, and in many cases prefetching actually degrades performance. We carry out quantitative and qualitative analyses of these tradeoffs and show that there is a linear relationship between overall performance and three metrics: percentages of misses prefetched, percentage of unused prefetches, and bandwidth.

关键词： computer algorithms HIGH technology BANDWIDTHS INTEGRATED circuits algorithms

来源：评论

学校读者我要写书评

暂无评论

Fractal analysis of time series in oil and gas production

引用

CHAOS SOLITONS & FRACTALS 2009年第5期41卷 2474-2483页

作者： Suleymanov, Arif A. Abbasov, Askar A. Ismaylov, Aydin J. Azerbaijan State Oil Acad Reservoir & Petr Engn Dept Baku AZ1010 Azerbaijan Salyan Oil Ltd ISR Plaza Business Ctr Baku AZ1000 Azerbaijan Caspian Energy Grp Baku AZ1069 Azerbaijan

The peculiarities of fractal characteristics' calculations for time series are described in this article. An algorithm for calculation of fractal dimension is suggested. it has been proved that the suggested method possesses high accuracy and the rapidity of convergence on the limited number of measurements compared to the methods of covering. The criteria of early diagnosis for changes in the condition of hydrodynamic processes, which do not vary by fractal dimension, have been recommended. The presented method is applicable for practical engineering calculations with self-affine, chaotic data, usually with relatively limited number of measurements. It is quite a simple method for calculation of fractal dimension, algorithm can be easily realized and it should be useful for engineers. The applicability of the proposed algorithm for fractal dimension calculation and early diagnosis criteria of qualitative changes in the behaviour of various dynamic systems has been tested both on simulated as well as practical examples of oil and gas production. (C) 2008 Elsevier Ltd. All rights reserved.

关键词： PETROLEUM industry GAS industry TIME series analysis FRACTALS computer algorithms HYDRODYNAMICS CHAOS theory ENGINEERING mathematics

来源：评论

学校读者我要写书评

暂无评论

Robust Tracking Control for Switched Fuzzy Systems with Fast Switching Controller

引用

MATHEMATICAL PROBLEMS IN ENGINEERING 2012年第1期2012卷 1-21页

作者： Yang, Hong Zhang, Le Liu, Xiaodong Shenyang Univ Sch Informat Engn Shenyang 110044 Peoples R China Dalian Univ Technol Sch Elect & Informat Engn Dalian 116023 Peoples R China

This paper addresses the problem of designing robust tracking controls for a class of switched fuzzy (SF) systems with time delay. A switched fuzzy system, which differs from existing ones, is firstly employed to describe a nonlinear system. Next, a fast switching controller consisting of a number of simple subcontrollers is proposed. The smooth transition is governed by using the fast switching controller. Tracking hybrid control schemes which are based upon a combination of the H-infinity tracking theory, fast switching control algorithm, and switching law design are developed such that the H-infinity model referent tracking performance is guaranteed. Since convex combination techniques are used to derive the delay independent criteria, some subsystems are allowed to be unstable. Finally, various comparisons of the elaborated examples are conducted to demonstrate the effectiveness of the proposed control design approach. All results illustrate good control performances as desired.

关键词： FUZZY systems NONLINEAR systems SYSTEMS theory SYSTEM analysis computer algorithms

来源：评论

学校读者我要写书评

暂无评论

An analysis of the compositional techniques in John!Chowning's Stria

引用

computer MUSIC JOURNAL 2007年第3期31卷 26-37页

作者： Meneghini, Matteo Univ Padua I-35131 Padua Italy

This article describes an analytic study of the process used by John Chowning for the composition of Stria. This article is intended to complete the description of the compositional process given in a previous work (Meneghini 2003), largely restated by Bossis in a subsequent paper (Bossis 2005). Stria was composed in 1977 and was fully generated by means of computer algorithms (Chowning 1977c) and the corresponding input files (Chowning 1977a, b): all the parameters of the sounds generated in Stria are determined and calculated by these algorithms on the basis of specific mathematical rules and of numerical parameters chosen by Mr. Chowning as input for the programs. For this reason, an accurate analysis of these algorithms is fundamental for a complete comprehension of the compositional process.

关键词： computer algorithms computer programming computer music ELECTRONIC music SOUND recordings PROGRAMMING languages (Electronic computers) ELECTRONIC data processing computer programmers

来源：评论

学校读者我要写书评

暂无评论

Detecting Local Community Structures in Networks Based on Boundary Identification

引用

MATHEMATICAL PROBLEMS IN ENGINEERING 2014年第1期2014卷 1-8页

作者： Liu Yang Ji Xin-sheng Liu Caixia Wang Ding Natl Digital Switching Syst Engn & Technol R&D Ct Zhengzhou 450002 Peoples R China Peking Univ Sch Elect Engn & Comp Sci Beijing 100871 Peoples R China

Detecting communities within networks is of great importance to understand the structure and organizations of real-world systems. To this end, one of the major challenges is to find the local community from a given node with limited knowledge of the global network. Most of the existing methods largely depend on the starting node and require predefined parameters to control the agglomeration procedure, which may cause disturbing inference to the results of local community detection. In this work, we propose a parameter-free local community detecting algorithm, which uses two self-adaptive phases in detecting the local community, thus comprehensively considering the external and internal link similarity of neighborhood nodes in each clustering iteration. Based on boundary nodes identification, our self-adaptive method can effectively control the scale and scope of the local community. Experimental results show that our algorithm is efficient and well-behaved in both computer-generated and real-world networks, greatly improving the performance of local community detection in terms of stability and accuracy.

关键词： COMMUNITY organization PARAMETER estimation ADAPTIVE control systems computer algorithms computer networks

来源：评论

学校读者我要写书评

暂无评论

Application of Large-Scale Inversion algorithms to Hydraulic Tomography in an Alluvial Aquifer

引用

GROUNDWATER 2017年第2期55卷 208-218页

作者： Fischer, P. Jardani, A. Ahmed, A. Soueid Abbas, M. Wang, X. Jourde, H. Lecoq, N. Normandie Univ M2C CNRS UNIROUENUNICAEN F-76000 Rouen France Imperial Coll London Dept Earth Sci & Engn London SW7 2AZ England Univ Montpellier CNRS Lab Hydrosci F-34000 Montpellier France

Large-scale inversion methods have been recently developed and permitted now to considerably reduce the computation time and memory needed for inversions of models with a large amount of parameters and data. In this work, we have applied a deterministic geostatistical inversion algorithm to a hydraulic tomography investigation conducted in an experimental field site situated within an alluvial aquifer in Southern France. This application aims to achieve a 2-D large-scale modeling of the spatial transmissivity distribution of the site. The inversion algorithm uses a quasi-Newton iterative process based on a Bayesian approach. We compared the results obtained by using three different methodologies for sensitivity analysis: an adjoint-state method, a finite-difference method, and a principal component geostatistical approach (PCGA). The PCGA is a large-scale adapted method which was developed for inversions with a large number of parameters by using an approximation of the covariance matrix, and by avoiding the calculation of the full Jacobian sensitivity matrix. We reconstructed high-resolution transmissivity fields (composed of up to 25,600 cells) which generated good correlations between the measured and computed hydraulic heads. In particular, we show that, by combining the PCGA inversion method and the hydraulic tomography method, we are able to substantially reduce the computation time of the inversions, while still producing high-quality inversion results as those obtained from the other sensitivity analysis methodologies.

关键词： AQUIFERS FLUVISOLS computer algorithms GEOLOGICAL statistics COVARIANCE matrices

来源：评论

学校读者我要写书评

暂无评论

RBF neural network based second-order sliding mode guidance for Mars entry under uncertainties

引用

AEROSPACE SCIENCE AND TECHNOLOGY 2015年第Jun.期43卷 226-235页

作者： Li, Shuang Jiang, Xiuqiang Nanjing Univ Aeronaut & Astronaut Coll Astronaut Nanjing 210016 Jiangsu Peoples R China Nanjing Univ Aeronaut & Astronaut Space New Technol Lab Nanjing 210016 Jiangsu Peoples R China

There are usually larger uncertainties in the atmosphere density of Mars and the aerodynamic parameters of entry vehicles, which inevitably degrades the performance of entry guidance and control algorithms. This paper studies the robust Mars atmospheric entry guidance design based on the radial basis function neural network (RBF-NN) and second-order sliding mode control (SOSMC). First, second-order sliding mode guidance (SOSMG) law is developed to robustly follow the pre-designed nominal trajectory under larger uncertainties and effectively reduce the longitudinal error. Then, the RBF neural network is included into the second-order sliding surface guidance law to online approximate the bounded uncertain terms and further improve the guidance accuracy. Finally, the effectiveness of the guidance algorithm proposed in this paper is confirmed by Monte Carlo simulations. (C) 2015 Elsevier Masson SAS. All rights reserved.

关键词： Uncertainty Sliding mode Neural network aerodynamic parameters Mars computer algorithms Guidance accuracy of guidance Radial basis function networks entry

来源：评论

学校读者我要写书评

暂无评论

Optimal Design of Clinical Tests for the Identification of Physiological Models of Type 1 Diabetes Mellitus

引用

INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 2009年第4期48卷 1989-2002页

作者： Galvanin, Federico Barolo, Massimiliano Macchietto, Sandro Bezzo, Fabrizio Univ Padua Dipartimento Principi & Impianti Ingn Chim I-35131 Padua Italy Univ London Imperial Coll Sci Technol & Med Dept Chem Engn London SW7 2AZ England

Type 1 diabetes mellitus is a disease affecting millions of people worldwide and causing the expenditure of millions of euros every year for health care. One of the most promising therapies derives from the use of an artificial pancreas, based on a control system able to maintain the normoglycaemia in the subject affected by diabetes. A dynamic simulation model of the glucose-insulin system can be useful in several circumstances for diabetes care, including testing of glucose sensors, insulin infusion algorithms, and decision support systems for diabetes. This paper considers the problem of the identification of single individual parameters in detailed dynamic models of glucose homeostasis. Optimal model-based design of experiment techniques are used to design a set of clinical tests that allow the model parameters to be estimated in a statistically sound way, while meeting constraints related to safety of the subject and ease of implementation. The model with the estimated set of parameters represents a specific subject and can thus be used for customized diabetes care solutions. Simulated results demonstrate how such an approach can improve the effectiveness of clinical tests and serve as a tool to devise safer and more efficient clinical protocols, thus providing a contribution to the development of an artificial pancreas.

关键词： DIABETES -- Treatment OPTIMAL designs (Statistics) CLINICAL trials ARTIFICIAL pancreases INSULIN pumps SIMULATION methods & models HOMEOSTASIS computer algorithms

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：