The ideal numerical simulation of 3D magnetotelluric was restricted by the methodology complexity and the time-consuming calculation. Boundary values, the variation of weighted residual equation, and the hexahedral me...
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The ideal numerical simulation of 3D magnetotelluric was restricted by the methodology complexity and the time-consuming calculation. Boundary values, the variation of weighted residual equation, and the hexahedral mesh generation method of finite element are three major causes. A finite element method for 3D magnetotelluric numerical modeling is presented in this paper as a solution for the problem mentioned above. In this algorithm, a hexahedral element coefficient matrix for magnetoelluric finite method is developed, which solves large-scale equations using preconditioned conjugate gradient of the first-type boundary conditions. This algorithm is verified using the homogeneous model, and the positive landform model, as well as the low resistance anomaly model.
System-level simulation has been widely used to evaluate system performance. Simulation methodologies have also been comprehensively discussed in different organizations or institutions. Most of the simulation methodo...
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System-level simulation has been widely used to evaluate system performance. Simulation methodologies have also been comprehensively discussed in different organizations or institutions. Most of the simulation methodologies proposed, however, mainly focus on one area of specific technologies. How to evaluate the performance of multiple air interface systems (e.g., cdma2000, WCDMA, WiMAX, ana their evolutions) in a fair and comprehensive manner has not been addressed extensively. This article presents a unified simulation methodology, including fading channel models, system configurations, and how to consider technology-dependent algorithms such as scheduling, overhead modeling, interference margin definition, and resource allocation based on system loading. This article uses this framework to compare three major existing radio technologies: cdma2000 1x EV-DO Rev. A, WCDMA HSPA, and mobile WiMAX based on 802.16e. Key simulation results based on our suggested system models and settings are presented and analyzed. It is shown that under our unified framework, the two CDMA systems exhibit higher spectrum efficiency than mobile WiMAX, especially on the downlink, while mobile WiMAX provides a higher peak rate.
One-class classification problem has been investigated thoroughly for past decades. Among one of the most effective neural network approaches for one-class classification, autoencoder has been successfully applied for...
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One-class classification problem has been investigated thoroughly for past decades. Among one of the most effective neural network approaches for one-class classification, autoencoder has been successfully applied for many applications. However, this classifier relies on traditional learning algorithms such as backpropagation to train the network, which is quite time-consuming. To tackle the slow learning speed in autoencoder neural network, we propose a simple and efficient one-class classifier based on extreme learning machine (ELM). The essence of ELM is that the hidden layer need not be tuned and the output weights can be analytically determined, which leads to much faster learning speed. The experimental evaluation conducted on several real-world benchmarks shows that the ELM based one-class classifier can learn hundreds of times faster than autoencoder and it is competitive over a variety of one-class classification methods.
The frequent items problem is to process a stream of items and find all those which occur more than a given fraction of the time. It is one of the most heavily studied problems in mining data streams, dating back to t...
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The frequent items problem is to process a stream of items and find all those which occur more than a given fraction of the time. It is one of the most heavily studied problems in mining data streams, dating back to the 1980s. Many other applications rely directly or indirectly on finding the frequent items, and implementations are in use in large-scale industrial systems. In this paper, we describe the most important algorithms for this problem in a common framework. We place the different solutions in their historical context, and describe the connections between them, with the aim of clarifying some of the confusion that has surrounded their properties. To further illustrate the different properties of the algorithms, we provide baseline implementations. This allows us to give empirical evidence that there is considerable variation in the performance of frequent items algorithms. The best methods can be implemented to find frequent items with high accuracy using only tens of kilobytes of memory, at rates of millions of items per second on cheap modern hardware.
作者：
Liu, YanhengRen, AnSun, DayangWang, AiminJilin Univ
Coll Comp Sci & Technol Changchun 130012 Jilin Peoples R China Jilin Univ
Minist Educ Key Lab Symbol Computat & Knowledge Engn Changchun 130012 Jilin Peoples R China Jilin Univ
Coll Commun Engn Changchun 130012 Jilin Peoples R China
A proactive topology control algorithm named PMD (Proactive Maintaining Algorithm for Dynamic Topology Control) is proposed for solving the problem of network partitioning. The algorithm controls the starting of BFS (...
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A proactive topology control algorithm named PMD (Proactive Maintaining Algorithm for Dynamic Topology Control) is proposed for solving the problem of network partitioning. The algorithm controls the starting of BFS (Breadth-First Search) by recognizing the addition of invalid nodes, monitoring the network structure dynamically. The definition, 'Communication Quality', is proposed to measure the quality of communications link. Only after network partitioning happens does PMD (Proactive Maintaining Algorithm for Dynamic Topology Control) start the link rebuilding mechanism to maintain the topology. The algorithm restrains isolated nodes generation and makes the energy be used efficiently. The results show that PMD (Proactive Maintaining Algorithm for Dynamic Topology Control) not only improves the efficiency of the energy, but also constructs a robust topology. (C) 2013 Elsevier Ltd. All rights reserved.
Data centers, as resource providers, take advantage of virtualization technology to achieve excellent resource utilization, scalability, and high availability. However, large numbers of computing servers containing vi...
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Data centers, as resource providers, take advantage of virtualization technology to achieve excellent resource utilization, scalability, and high availability. However, large numbers of computing servers containing virtual machines of data centers consume a tremendous amount of energy. Thus, it is necessary to significantly improve resource utilization. Among the many issues associated with energy, scheduling plays a very important role in successful task execution and energy consumption in virtualized environments. This paper seeks to implement an energy-efficient task scheduling algorithm for virtual machines with changeless speed comprised of two main steps: assigning as many tasks as possible to virtual machines with lower energy consumption and keeping the makespan of each virtual machine within a deadline. We propose a novel scheduling algorithm for heterogeneous virtual machines in virtualized environments to effectively reduce energy consumption and finish all tasks before a deadline. The new scheduling strategy is simulated using the CloudSim toolkit package. Experimental results show that our approach outperforms previous scheduling methods by a significant margin in terms of energy consumption.
Redundant call elimination has been an important program optimisation process as it can produce super-linear speedup in optimised programs. In this paper, we investigate use of the tupling transformation in achieving ...
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Redundant call elimination has been an important program optimisation process as it can produce super-linear speedup in optimised programs. In this paper, we investigate use of the tupling transformation in achieving this optimisation over a first-order functional language. Standard tupling technique, as described in [6], works excellently in a restricted variant of the language;namely, functions with single recursion argument. We provide a semantic understanding of call redundancy, upon which we construct an analysis for handling the tupling of functions with multiple recursion arguments. The analysis provides a means to ensure termination of the tupling transformation. As the analysis is of polynomial complexity, it makes the tupling suitable as a step in compiler optimisation.
We give the first example of a binary pattern which is Abelian 2-avoidable, but which contains no Abelian fourth power. We introduce a family {fn}(n=1)(infinity) of binary morphisms which offer a common generalization...
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We give the first example of a binary pattern which is Abelian 2-avoidable, but which contains no Abelian fourth power. We introduce a family {fn}(n=1)(infinity) of binary morphisms which offer a common generalization of the Fibonacci morphism and the Abelian fourth-power-free morphism of Dekking. We show that the Fibonacci word begins with arbitrarily high Abelian powers, but for n >= 2, the fixed point of f(n) avoids x(n+2) in the Abelian sense. The sets of patterns avoided in the Abelian sense by the fixed points of f(n) and f(n+1) are mutually incomparable for n >= 2.
The article features the technical development in the process of designing public-key cryptography to protect international commerce and communications. In 1997, the National Institute of Standards and Technology (NIS...
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The article features the technical development in the process of designing public-key cryptography to protect international commerce and communications. In 1997, the National Institute of Standards and Technology (NIST) announced a competition for the algorithm, Data Encryption Standard replacement, and held public meetings to discuss the criteria for a proposed Advanced Encryption Standard (AES) with much focus on its key length. NIST allowed foreign participation in the AES competition, settling requirements like implementation of symmetric key cryptography, must of an algorithm to be a block cipher, designing 128-bit blocks algorithm and to have three key sizes of 128, 192 and 256 bits. While designing, nonlinear functions form the basis of cryptographic design. Simplest techniques for encrypting a block of symbols are substitution, which replaces a symbol by another and transposition permutes the symbols of a block around. The purpose of a cryptosystem is to make decryption of messages extremely difficult without the key and the design of a cryptosystem has a dual objective, ensuring difficulty in cryptanalysis while enabling certification of the algorithm's security. Block-structured algorithms, whose non-linearity is achieved by substitution boxes attacked by differential and linear cryptanalysis.
Reversible digital watermarking techniques enable the recovery of the original 'cover image' from a watermarked image in a distortion-free way. Reversible watermarking techniques find application in military a...
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Reversible digital watermarking techniques enable the recovery of the original 'cover image' from a watermarked image in a distortion-free way. Reversible watermarking techniques find application in military and medical imagery, where integrity of the cover image is of utmost importance. However, in practice, many military data transmissions occur over communication channels whose noise levels are so high that the receiving system is unable to correct all errors in the received data. In such a case, the authors are bound to get non-zero distortion in the recovered cover image as well as the extracted watermark, in spite of using reversible watermarking techniques. In this study, they investigate the effect of high data error rates on different state-of-the-art reversible watermarking algorithms. Their simulation results help to choose the most suitable reversible watermarking scheme, depending on whether the distortion of the retrieved cover image or the distortion of the retrieved watermark is the primary concern.
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