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Virtually scaling-free adaptive CORDIC rotator

IEE PROCEEDINGS-computerS AND DIGITAL TECHNIQUES 2004年第6期151卷 448-456页

作者： Maharatna, K Troya, A Banerjee, S Grass, E Univ Bristol Dept Elect & Elect Engn Bristol Avon England Inst High Performance Microelect D-15236 Frankfurt Germany Indian Inst Technol Dept Elect & Elect Commun Engn Kharagpur 721302 W Bengal India

The authors propose a coordinate rotation digital computer (CORDIC) rotator algorithm that eliminates the problems of scale factor compensation and limited range of convergence associated with the classical CORDIC algorithm. In the proposed scheme, depending on the target angle or the initial coordinate of the vector, a scaling by 1 or 1/root2 is needed that can be realised with minimal hardware. The proposed CORDIC rotator adaptively selects the appropriate iteration steps and converges to the final result by executing on average only 50% of the number of iterations required by the classical CORDIC. Unlike for the classical CORDIC, the value of the scale factor is completely independent of the number of executed iterations. Based on the proposed algorithm, a 16-bit pipelined CORDIC rotator was implemented. The silicon area of the fabricated pipelined CORDIC rotator core is 2.73 mm(2). This is equivalent to 38 000 inverter gates in the used 0.25 mum BiCMOS technology. The average dynamic power consumption of the fabricated CORDIC rotator is 17 mW at a 2.5 V supply voltage and a 20 Ms/s throughput. Currently, this CORDIC rotator is used as a part of the baseband processor for a project that aims to design a single-chip wireless modem compliant with the IEEE 802.11a standard.

关键词： computerS CORDIC algorithm computer algorithms DATA transmission systems DIGITAL communications ELECTRONIC data processing ELECTRONIC systems

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Stochastic optimization model of locomotive assignment to freight trains

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AUTOMATION AND REMOTE CONTROL 2016年第11期77卷 1944-1956页

作者： Ivanov, S. V. Kibzun, A. I. Osokin, A. V. Natl Res Univ Moscow State Aviat Inst Moscow Russia

Consideration was given to the optimization model of assigning the locomotives to the freight trains. The model was formulated in terms of a dynamic problem of stochastic programming with probabilistic constraints. The state variables characterize positions of the locomotives and trains at each time instant. The variables defining the motion of locomotives and their assignment to trains at each time instant play the role of controls. The expectation of the total freight traffic is the criterial function of the problem. A two-stage hybrid algorithm to solve the problem was developed. It combines the coordinatewise search and a genetic algorithm. Results of the numerical experiment were given.

关键词： MATHEMATICAL optimization STOCHASTIC analysis LOCOMOTIVES CONSTRAINT satisfaction (Artificial intelligence) computer algorithms

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Sample-Based Extreme Learning Machine with Missing Data

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MATHEMATICAL PROBLEMS IN ENGINEERING 2015年第1期2015卷 1-11页

作者： Gao, Hang Liu, Xin-Wang Peng, Yu-Xing Jian, Song-Lei Natl Univ Def Technol Sci & Technol Parallel & Distributed Proc Lab Changsha 410073 Hunan Peoples R China

Extreme learning machine (ELM) has been extensively studied in machine learning community during the last few decades due to its high efficiency and the unification of classification, regression, and so forth. Though bearing such merits, existing ELM algorithms cannot efficiently handle the issue of missing data, which is relatively common in practical applications. The problem of missing data is commonly handled by imputation (i.e., replacing missing values with substituted values according to available information). However, imputation methods are not always effective. In this paper, we propose a sample-based learning framework to address this issue. Based on this framework, we develop two sample-based ELM algorithms for classification and regression, respectively. Comprehensive experiments have been conducted in synthetic data sets, UCI benchmark data sets, and a real world fingerprint image data set. As indicated, without introducing extra computational complexity, the proposed algorithms do more accurate and stable learning than other state-of-the-art ones, especially in the case of higher missing ratio.

关键词： MACHINE learning MISSING data (Statistics) REGRESSION analysis BIG data computer algorithms

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Refined typing to localize the impact of forced strictness on free theorems

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ACTA INFORMATICA 2011年第3期48卷 191-211页

作者： Seidel, Daniel Voigtlaender, Janis Univ Bonn Inst Comp Sci D-53117 Bonn Germany

Free theorems establish interesting properties of parametrically polymorphic functions, solely from their types, and serve as a nice proof tool. For pure and lazy functional programming languages, they can be used with very few preconditions. Unfortunately, in the presence of selective strictness, as provided in languages like Haskell, their original strength is reduced. In this paper we present an approach for overcoming this weakness in specific situations. Employing a refined type system which tracks the use of enforced strict evaluation, we rule out unnecessary restrictions that otherwise emerge. Additionally, we provide (and implement) an algorithm determining all refined types for a given term.

关键词： PROGRAMMING languages (Electronic computers) PROOF theory SUBROUTINES (computer programs) computer algorithms computer programming FUNCTIONAL programming (computer science) HASKELL (computer program language)

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Extracting geometric attributes directly from scanned data sets for feature recognition

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INTERNATIONAL JOURNAL OF computer INTEGRATED MANUFACTURING 2002年第1期15卷 50-61页

作者： Jun, YT Raja, VH Korea Inst Sci & Technol CAD CAM Res Ctr Seoul 136792 South Korea Univ Warwick Int Mfg Ctr Warwick Mfg Grp Coventry CV4 7AL W Midlands England

Reverse engineering (RE) is the process of digitally capturing physical entities of an existing part from its scanned data. A novel methodology is proposed for reconstruction of CAD models by recognizing prismatic features from a data set of three-dimensional scanned points, which utilizes the concepts of artificial neural networks (ANNs). Four geometric attributes, such as chain code, convex/concave, circular/rectangular, and open/closed attribute, are extracted from a scanned point set first, and then they are presented to the ANN module for feature recognition. Each generic feature in the feature library is uniquely described by those geometric attributes. Identifying each feature requires the determination of these attributes beforehand. Once these attributes are determined, a segmented point set may be uniquely identified as a valid feature through the ANN module. Since feature recognition is carried out based on these attributes, this paper focuses on algorithms for determining these attributes directly from a scanned point set. The system validation and sample results are also discussed.

关键词： computer algorithms REVERSE engineering

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Direct Frequency Changer Operation Under a New Scalar Control Algorithm

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IEEE TRANSACTIONS ON POWER ELECTRONICS 1991年第1期6卷 100-107页

作者： Roy, Gilles April, Georges-Emile Ecole Polytech Dept Elect Engn POB 6079Stn A Montreal PQ H3C 3A7 Canada

A thorough analysis of a new scalar control method for the operation of direct frequency changers using bidirectional switches operating at high switching frequencies is proposed. The method uses the instantaneous voltage ratio of specific input phase voltages to generate the active and zero states of the various switches. A voltage transfer ratio as high as 0.87 is obtained under synchronous and asynchronous operation with a conventionally connected three phase load. Moreover, the converter operation can be set to produce almost any power displacement factor, independent of load power factor.

关键词： full control phase voltage voltage ratio DFC transfer ratio Job Ladders Frequency spectra Surgery computer algorithms asynchronous operation Frequency converters output ports output voltage scalar control loading characteristics

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A Collaborative Neighbor Representation Based Face Recognition Algorithm

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MATHEMATICAL PROBLEMS IN ENGINEERING 2013年第1期2013卷 1-9页

作者： Li, Zhengming Zhu, Qi Xie, Binglei Cao, Jian Zhang, Jin Guangdong Polytech Normal Univ Guangdong Ind Training Ctr Guangzhou 510665 Guangdong Peoples R China Harbin Inst Technol Shenzhen Grad Sch Biocomp Res Ctr Shenzhen 518005 Peoples R China Shenzhen Key Lab Urban Planning & Decis Making Si Shenzhen Peoples R China

We propose a new collaborative neighbor representation algorithm for face recognition based on a revised regularized reconstruction error (RRRE), called the two-phase collaborative neighbor representation algorithm (TCNR). Specifically, the RRRE is the division of l(2)-norm of reconstruction error of each class into a linear combination of l(2)-norm of reconstruction coefficients of each class, which can be used to increase the discrimination information for classification. The algorithmis as follows: in the first phase, the test sample is represented as a linear combination of all the training samples by incorporating the neighbor information into the objective function. In the second phase, we use the.. classes to represent the test sample and calculate the collaborative neighbor representation coefficients. TCNR not only can preserve locality and similarity information of sparse coding but also can eliminate the side effect on the classification decision of the class that is far from the test sample. Moreover, the rationale and alternative scheme of TCNR are given. The experimental results show that TCNR algorithm achieves better performance than seven previous algorithms.

关键词： HUMAN face recognition (computer science) REPRESENTATION theory (Algebra) computer algorithms PERFORMANCE evaluation COEFFICIENTS (Statistics)

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Ensemble based collaborative and distributed intrusion detection systems: A survey

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JOURNAL OF NETWORK AND computer APPLICATIONS 2016年 66卷 1-16页

作者： Folino, Gianluigi Sabatino, Pietro ICAR CNR Ist Calcolo & Reti Ad Alte Prestaz Via P Bucci I-87036 Arcavacata Di Rende CS Italy

Modern network intrusion detection systems must be able to handle large and fast changing data, often also taking into account real-time requirements. Ensemble-based data mining algorithms and their distributed implementations are a promising approach to these issues. Therefore, this work presents the current state of the art of the ensemble-based methods used in modern intrusion detection systems, with a particular attention to distributed approaches and implementations. This review also consider supervised and unsupervised data mining algorithms, more suitable to work in an environment that requires the analysis of data streams in real-time. Sharing knowledge across multiple nodes is another of the key points in designing appropriate NIDSs and for this reason, collaborative IDS were also included in this work. Finally, we discuss some open issues and lessons learned from this review, which can help researchers to design more efficient NIDSs. (C) 2016 Elsevier Ltd. All rights reserved.

关键词： Data mining computer algorithms Real-time computing Data analysis Intrusion detection systems (computer security) Ensembles (Mathematics)

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PARTICLE SWARM OPTIMIZATION-BASED ALGORITHM FOR BILEVEL JOINT PRICING AND LOT-SIZING DECISIONS IN A SUPPLY CHAIN

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APPLIED ARTIFICIAL INTELLIGENCE 2013年第6期27卷 441-460页

作者： Ma, Weimin Wang, Miaomiao Tongji Univ Sch Econ & Management Shanghai 200092 Peoples R China

This study considers joint pricing and lot-sizing policies in a single-manufacturer-single-retailer system. Because a supply chain is a hierarchical system, we adopt a bilevel programming technique to establish a bilevel joint pricing and lot-sizing model guided by the manufacturer. The objective of the problem here is to respectively maximize the manufacturer's and the retailer's net profits by determining the manufacturer's and retailer's lot size, the wholesale price and the retail price simultaneously. Following the properties of the bilevel programming problem (BLPP), we design a novel bilevel particle swarm optimization algorithm (BPSO), and it can solve BLPP without any assumed conditions of the problem. BPSO shows a good performance on eight benchmark bilevel problems. Then BPSO is employed to solve the proposed bilevel model, and the experimental data are used to analyze the features of the proposed bilevel model, and the results support the finding that BPSO is effective in optimizing BLPP.

关键词： PARAMETER estimation computer algorithms DECISION making SUPPLY chains BILEVEL programming RETAIL industry MATHEMATICAL models

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Measurement of packet loss probability by optimal design of packet probing experiments

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IET COMMUNICATIONS 2009年第6期3卷 979-991页

作者： Parker, B. M. Gilmour, S. G. Schormans, J. Queen Mary Univ London London England

Packet-level measurement is now critical to many aspects of broadband networking, for example for guaranteeing service level agreements, facilitating measurement-based admission control algorithms and performing network tomography. Because it is often impossible to measure all the data passing across a network, the most widely used method of measurement works by injecting probe packets. The probes provide samples of the packet loss and delay, and from these samples the loss and delay performance of the traffic as a whole can be deduced. However, measuring performance like this is prone to errors. Recent work has shown that some of these errors are minimised by using a gamma renewal process as the optimal pattern for the time instants at which to inject probes. This leaves the best rate at which to inject probes as the key unsolved problem, and this is addressed here by using the statistical principles of the design of experiments. The experimental design approach allows one to treat packet-level measurements as numerical experiments that can be designed optimally. Modelling the overflow of buffers as a 2-state Markov chain, the system's likelihood function is deduced, and from this a technique ( using the Fisher information matrix) to determine the upper-bound on the optimal rate of probing is developed. A generalisation of this method accounts for the effect of the probed observations interfering with the experiment. The numerical results focus on VoIP traffic, allowing one to show how this methodology would be used in practice. One application of this is in measurement-based admission control algorithms, where the technique can be used to provide an upper-bound on the rate at which probes should be injected to monitor the loss performance of the target network, prior to making an admit/do not admit decision.

关键词： Packet loss information matrix Overflow computer algorithms Uppers loss probability design theory Traffic Optimal design Packet packet-level Exploration with a probe Service level agreements Admission control

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