Acceleration of Expectation-Maximization algorithm for length-biased right-censored data.
Chan, Kwun Chuen Gary
2017-01-01
Vardi's Expectation-Maximization (EM) algorithm is frequently used for computing the nonparametric maximum likelihood estimator of length-biased right-censored data, which does not admit a closed-form representation. The EM algorithm may converge slowly, particularly for heavily censored data. We studied two algorithms for accelerating the convergence of the EM algorithm, based on iterative convex minorant and Aitken's delta squared process. Numerical simulations demonstrate that the acceleration algorithms converge more rapidly than the EM algorithm in terms of number of iterations and actual timing. The acceleration method based on a modification of Aitken's delta squared performed the best under a variety of settings.
An improved EZBC algorithm based on block bit length
Wang, Renlong; Ruan, Shuangchen; Liu, Chengxiang; Wang, Wenda; Zhang, Li
2011-12-01
Embedded ZeroBlock Coding and context modeling (EZBC) algorithm has high compression performance. However, it consumes large amounts of memory space because an Amplitude Quadtree of wavelet coefficients and other two link lists would be built during the encoding process. This is one of the big challenges for EZBC to be used in real time or hardware applications. An improved EZBC algorithm based on bit length of coefficients was brought forward in this article. It uses Bit Length Quadtree to complete the coding process and output the context for Arithmetic Coder. It can achieve the same compression performance as EZBC and save more than 75% memory space required in the encoding process. As Bit Length Quadtree can quickly locate the wavelet coefficients and judge their significance, the improved algorithm can dramatically accelerate the encoding speed. These improvements are also beneficial for hardware. PACS: 42.30.Va, 42.30.Wb
On Fast Algorithm for Computing Even-Length DCT
Reznik, Yuriy A
2010-01-01
We study recursive algorithm for computing DCT of lengths $N=q 2^m$ ($m,q \\in \\mathbb{N}$, $q$ is odd) due to C.W.Kok. We show that this algorithm has the same multiplicative complexity as theoretically achievable by the prime factor decomposition, when $m \\leqslant 2$. We also show that C.W.Kok's factorization allows a simple conversion to a scaled form. We analyze complexity of such a scaled factorization, and show that for some lengths it achieves lower multiplicative complexity than one of known prime factor-based scaled transforms.
Minimal-Length Interoperability Test Sequences Generation via Genetic Algorithm
Institute of Scientific and Technical Information of China (English)
ZHONG Ning; KUANG Jing-ming; HE Zun-wen
2008-01-01
A novel interoperability test sequences optimization scheme is proposed in which the genetic algo-rithm(GA)is used to obtain the minimal-length interoperability test sequences.During our work,the basicin teroperability test sequences are generated based on the minimal-complete-coverage criterion,which removes the redundancy from conformance test sequences.Then interoperability sequences minimization problem can be considered as an instance of the set covering problem,and the GA is applied to remove redundancy in interoperability transitions.The results show that compared to conventional algorithm,the proposed algorithm is more practical to avoid the state space explosion problem,for it can reduce the length of the test sequences and maintain the same transition coverage.
The PX-EM algorithm for fast stable fitting of Henderson's mixed model
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Van Dyk David A
2000-03-01
Full Text Available Abstract This paper presents procedures for implementing the PX-EM algorithm of Liu, Rubin and Wu to compute REML estimates of variance covariance components in Henderson's linear mixed models. The class of models considered encompasses several correlated random factors having the same vector length e.g., as in random regression models for longitudinal data analysis and in sire-maternal grandsire models for genetic evaluation. Numerical examples are presented to illustrate the procedures. Much better results in terms of convergence characteristics (number of iterations and time required for convergence are obtained for PX-EM relative to the basic EM algorithm in the random regression.
An extended EM algorithm for subspace clustering
Institute of Scientific and Technical Information of China (English)
Lifei CHEN; Qingshan JIANG
2008-01-01
Clustering high dimensional data has become a challenge in data mining due to the curse of dimension-ality. To solve this problem, subspace clustering has been defined as an extension of traditional clustering that seeks to find clusters in subspaces spanned by different combinations of dimensions within a dataset. This paper presents a new subspace clustering algorithm that calcu-lates the local feature weights automatically in an EM-based clustering process. In the algorithm, the features are locally weighted by using a new unsupervised weight-ing method, as a means to minimize a proposed cluster-ing criterion that takes into account both the average intra-clusters compactness and the average inter-clusters separation for subspace clustering. For the purposes of capturing accurate subspace information, an additional outlier detection process is presented to identify the pos-sible local outliers of subspace clusters, and is embedded between the E-step and M-step of the algorithm. The method has been evaluated in clustering real-world gene expression data and high dimensional artificial data with outliers, and the experimental results have shown its effectiveness.
Institute of Scientific and Technical Information of China (English)
Xianbin Wen; Hua Zhang; Jianguang Zhang; Xu Jiao; Lei Wang
2009-01-01
A novel method that hybridizes genetic algorithm (GA) and expectation maximization (EM) algorithm for the classification of syn-thetic aperture radar (SAR) imagery is proposed by the finite Gaussian mixtures model (GMM) and multiscale autoregressive (MAR)model. This algorithm is capable of improving the global optimality and consistency of the classification performance. The experiments on the SAR images show that the proposed algorithm outperforms the standard EM method significantly in classification accuracy.
Video segmentation using multiple features based on EM algorithm
Institute of Scientific and Technical Information of China (English)
张风超; 杨杰; 刘尔琦
2004-01-01
Object-based video segmentation is an important issue for many multimedia applications. A video segmentation method based on EM algorithm is proposed. We consider video segmentation as an unsupervised classification problem and apply EM algorithm to obtain the maximum-likelihood estimation of the Gaussian model parameters for model-based segmentation. We simultaneously combine multiple features (motion, color) within a maximum likelihood framework to obtain accurate segment results. We also use the temporal consistency among video frames to improve the speed of EM algorithm. Experimental results on typical MPEG-4 sequences and real scene sequences show that our method has an attractive accuracy and robustness.
Relaxation of the EM Algorithm via Quantum Annealing
Miyahara, Hideyuki
2016-01-01
The EM algorithm is a novel numerical method to obtain maximum likelihood estimates and is often used for practical calculations. However, many of maximum likelihood estimation problems are nonconvex, and it is known that the EM algorithm fails to give the optimal estimate by being trapped by local optima. In order to deal with this difficulty, we propose a deterministic quantum annealing EM algorithm by introducing the mathematical mechanism of quantum fluctuations into the conventional EM algorithm because quantum fluctuations induce the tunnel effect and are expected to relax the difficulty of nonconvex optimization problems in the maximum likelihood estimation problems. We show a theorem that guarantees its convergence and give numerical experiments to verify its efficiency.
A Trust Region Aggressive Space Mapping Algorithm for EM
DEFF Research Database (Denmark)
Bakr., M.; Bandler, J. W.; Biernacki, R.;
1998-01-01
A robust new algorithm for electromagnetic (EM) optimization of microwave circuits is presented. The algorithm (TRASM) integrates a trust region methodology with the aggressive space mapping (ASM). The trust region ensures that each iteration results in improved alignment between the coarse and f...
A modified EM algorithm for estimation in generalized mixed models.
Steele, B M
1996-12-01
Application of the EM algorithm for estimation in the generalized mixed model has been largely unsuccessful because the E-step cannot be determined in most instances. The E-step computes the conditional expectation of the complete data log-likelihood and when the random effect distribution is normal, this expectation remains an intractable integral. The problem can be approached by numerical or analytic approximations; however, the computational burden imposed by numerical integration methods and the absence of an accurate analytic approximation have limited the use of the EM algorithm. In this paper, Laplace's method is adapted for analytic approximation within the E-step. The proposed algorithm is computationally straightforward and retains much of the conceptual simplicity of the conventional EM algorithm, although the usual convergence properties are not guaranteed. The proposed algorithm accommodates multiple random factors and random effect distributions besides the normal, e.g., the log-gamma distribution. Parameter estimates obtained for several data sets and through simulation show that this modified EM algorithm compares favorably with other generalized mixed model methods.
Three penalized EM-type algorithms for PET image reconstruction.
Teng, Yueyang; Zhang, Tie
2012-06-01
Based on Bayes theory, Green introduced the maximum a posteriori (MAP) algorithm to obtain a smoothing reconstruction for positron emission tomography. This algorithm is flexible and convenient for most of the penalties, but it is hard to guarantee convergence. For a common goal, Fessler penalized a weighted least squares (WLS) estimator by a quadratic penalty and then solved it with the successive over-relaxation (SOR) algorithm, however, the algorithm was time-consuming and difficultly parallelized. Anderson proposed another WLS estimator for faster convergence, on which there were few regularization methods studied. For three regularized estimators above, we develop three new expectation maximization (EM) type algorithms to solve them. Unlike MAP and SOR, the proposed algorithms yield update rules by minimizing the auxiliary functions constructed on the previous iterations, which ensure the cost functions monotonically decreasing. Experimental results demonstrated the robustness and effectiveness of the proposed algorithms.
A Constrained EM Algorithm for Independent Component Analysis
Welling, Max; Weber, Markus
2001-01-01
We introduce a novel way of performing independent component analysis using a constrained version of the expectation-maximization (EM) algorithm. The source distributions are modeled as D one-dimensional mixtures of gaussians. The observed data are modeled as linear mixtures of the sources with additive, isotropic noise. This generative model is fit to the data using constrained EM. The simpler “soft-switching” approach is introduced, which uses only one parameter to decide on the sub- or sup...
The threshold EM algorithm for parameter learning in bayesian network with incomplete data
Lamine, Fradj Ben; Mahjoub, Mohamed Ali
2012-01-01
Bayesian networks (BN) are used in a big range of applications but they have one issue concerning parameter learning. In real application, training data are always incomplete or some nodes are hidden. To deal with this problem many learning parameter algorithms are suggested foreground EM, Gibbs sampling and RBE algorithms. In order to limit the search space and escape from local maxima produced by executing EM algorithm, this paper presents a learning parameter algorithm that is a fusion of EM and RBE algorithms. This algorithm incorporates the range of a parameter into the EM algorithm. This range is calculated by the first step of RBE algorithm allowing a regularization of each parameter in bayesian network after the maximization step of the EM algorithm. The threshold EM algorithm is applied in brain tumor diagnosis and show some advantages and disadvantages over the EM algorithm.
On-line EM algorithm for the normalized gaussian network.
Sato, M; Ishii, S
2000-02-01
A normalized gaussian network (NGnet) (Moody & Darken, 1989) is a network of local linear regression units. The model softly partitions the input space by normalized gaussian functions, and each local unit linearly approximates the output within the partition. In this article, we propose a new on-line EMalgorithm for the NGnet, which is derived from the batch EMalgorithm (Xu, Jordan, &Hinton 1995), by introducing a discount factor. We show that the on-line EM algorithm is equivalent to the batch EM algorithm if a specific scheduling of the discount factor is employed. In addition, we show that the on-line EM algorithm can be considered as a stochastic approximation method to find the maximum likelihood estimator. A new regularization method is proposed in order to deal with a singular input distribution. In order to manage dynamic environments, where the input-output distribution of data changes over time, unit manipulation mechanisms such as unit production, unit deletion, and unit division are also introduced based on probabilistic interpretation. Experimental results show that our approach is suitable for function approximation problems in dynamic environments. We also apply our on-line EM algorithm to robot dynamics problems and compare our algorithm with the mixtures-of-experts family.
An arc-length warping algorithm for gesture recognition using quaternion representation.
Cifuentes, Jenny; Pham, Minh Tu; Moreau, Richard; Prieto, Flavio; Boulanger, Pierre
2013-01-01
This paper presents a new algorithm, called Dynamic Arc-Length Warping algorithm (DALW) for hand gesture recognition based on the orientation data. In this algorithm, after calculating the quaternion for each orientation measurement, we use DALW algorithm to obtain a similarity measure between different trajectories. We present the benefits of using quaternion alongside the implementation of Dynamic Arc Length Warping to present an optimized tool for gesture recognition.We show the advantages of this approach compared with other techniques. This tool can be used to distinguish similar and different gestures. An experimental validation is carried out to classify a series of simple human gestures.
An Algorithm for Variable-Length Proper-Name Compression
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James L. Dolby
1970-12-01
Full Text Available Viable on-line search systems require reasonable capabilities to automatically detect (and hopefully correct variations between request format and stored format. An important requirement is the solution of the problem of matching proper names, not only because both input specifications and storage specifications are subject to error, but also because various transliteration schemes exist and can provide variant proper name forms in the same data base. This paper reviews several proper name matching schemes and provides an updated version of these schemes which tests out nicely on the proper name equivalence classes of a suburban telephone book. An appendix lists the corpus of names used for algorithm test.
Minimum-distortion isometric shape correspondence using EM algorithm.
Sahillioğlu, Yusuf; Yemez, Yücel
2012-11-01
We present a purely isometric method that establishes 3D correspondence between two (nearly) isometric shapes. Our method evenly samples high-curvature vertices from the given mesh representations, and then seeks an injective mapping from one vertex set to the other that minimizes the isometric distortion. We formulate the problem of shape correspondence as combinatorial optimization over the domain of all possible mappings, which then reduces in a probabilistic setting to a log-likelihood maximization problem that we solve via the Expectation-Maximization (EM) algorithm. The EM algorithm is initialized in the spectral domain by transforming the sampled vertices via classical Multidimensional Scaling (MDS). Minimization of the isometric distortion, and hence maximization of the log-likelihood function, is then achieved in the original 3D euclidean space, for each iteration of the EM algorithm, in two steps: by first using bipartite perfect matching, and then a greedy optimization algorithm. The optimal mapping obtained at convergence can be one-to-one or many-to-one upon choice. We demonstrate the performance of our method on various isometric (or nearly isometric) pairs of shapes for some of which the ground-truth correspondence is available.
An Efficient Algorithm for the Discrete Gabor Transform using full length Windows
DEFF Research Database (Denmark)
Søndergaard, Peter Lempel
2009-01-01
This paper extends the efficient factorization of the Gabor frame operator developed by Strohmer (1998) to the Gabor analysis/synthesis operator. This provides a fast method for computing the discrete Gabor transform (DGT) and several algorithms associated with it. The algorithm is used for the c...... for the case when the involved window and signal have the same length....
An Efficient Algorithm for the Discrete Gabor Transform using full length Windows
DEFF Research Database (Denmark)
Søndergaard, Peter Lempel
2007-01-01
This paper extends the efficient factorization of the Gabor frame operator developed by Strohmer in [1] to the Gabor analysis/synthesis operator. This provides a fast method for computing the discrete Gabor transform (DGT) and several algorithms associated with it. The algorithm is used for the c...... for the case when the involved window and signal have the same length....
A computational algorithm addressing how vessel length might depend on vessel diameter.
Cai, Jing; Zhang, Shuoxin; Tyree, Melvin T
2010-07-01
The objective of this method paper was to examine a computational algorithm that may reveal how vessel length might depend on vessel diameter within any given stem or species. The computational method requires the assumption that vessels remain approximately constant in diameter over their entire length. When this method is applied to three species or hybrids in the genus Populus, vessel length is sometimes a linear function of vessel diameter and sometimes an exponential function of vessel diameter within a stem, based on R(2) values. Our results give within-species variation of vessel length versus diameter, and we compare this to between-species variation of mean diameter versus mean length.
A computational algorithm addressing how vessel length might depend on vessel diameter
Jing Cai; Shuoxin Zhang; Melvin T. Tyree
2010-01-01
The objective of this method paper was to examine a computational algorithm that may reveal how vessel length might depend on vessel diameter within any given stem or species. The computational method requires the assumption that vessels remain approximately constant in diameter over their entire length. When this method is applied to three species or hybrids in the...
Pedestrian Stride Length Estimation from IMU Measurements and ANN Based Algorithm
Directory of Open Access Journals (Sweden)
Haifeng Xing
2017-01-01
Full Text Available Pedestrian dead reckoning (PDR can be used for continuous position estimation when satellite or other radio signals are not available, and the accuracy of the stride length measurement is important. Current stride length estimation algorithms, including linear and nonlinear models, consider a few variable factors, and some rely on high precision and high cost equipment. This paper puts forward a stride length estimation algorithm based on a back propagation artificial neural network (BP-ANN, using a consumer-grade inertial measurement unit (IMU; it then discusses various factors in the algorithm. The experimental results indicate that the error of the proposed algorithm in estimating the stride length is approximately 2%, which is smaller than that of the frequency and nonlinear models. Compared with the latter two models, the proposed algorithm does not need to determine individual parameters in advance if the trained neural net is effective. It can, thus, be concluded that this algorithm shows superior performance in estimating pedestrian stride length.
EM algorithm and its application to testing hypotheses
Institute of Scientific and Technical Information of China (English)
房祥忠; 陈家鼎
2003-01-01
The conventional method for testing hypotheses is to find an exact or asymptotic distributionof a test statistic. But when the model is complex and the sample size is small, difficulty often arises. Thispaper aims to present a method for finding maximum probability with the help of EM algorithm. For any fixedsample size, this method can be used not only to obtain an accurate test but also to check the real level ofa test which is build by large sample theory. Especially, while doing this, one needs neither the accurate norasymptotic distribution of the test statistic. So the method is easily performed and is especially useful for small samples.
ESTIMATION OF THE LENGTH CONSTANT OF A LONG COOLING FIN BY AN ANCIENT CHINESE ALGORITHM
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Lan Xu
2011-01-01
Full Text Available In this paper, an ancient Chinese algorithm is used to estimate the length constant of a long cooling fin, and an approximate solution formulation is obtained. The obtained results show that this method is a simple but promising method without any requirement for advanced calculus.
AN ALGORITHM OF LOCAL PREDICTION FOR CHAOTIC SEQUENCES WITH VARIABLE FRAME LENGTH
Institute of Scientific and Technical Information of China (English)
Li Jinlong; Lin Jiayu
2012-01-01
According to the issues that the predict errors of chaotic sequences rapidly accumulated in multi-step forecasting which affects the predict accuracy,we proposed a new predict algorithm based on local modeling with variable frame length and interpolation points.The core idea is that,using interpolation method to increase the available sample data,then modeling the chaos dynamics system with least square algorithm which based on the Bernstein polynomial to realize the forecasting.We use the local modeling method,looking for the optimum frame length and interpolation points in every frame to improve the predict peformance.The experimental results show that the proposed algorithm can improve the predictive ability effectively,decreasing the accumulation of iterative errors in multi-step prediction.
Heavy traffic queue length behavior in a switch under the MaxWeight algorithm
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Siva Theja Maguluri
2016-11-01
Full Text Available We consider a switch operating under the MaxWeight scheduling algorithm, under any traffic pattern such that all the ports are loaded. This system is interesting to study since the queue lengths exhibit a multi-dimensional state-space collapse in the heavy-traffic regime. We use a Lyapunov-type drift technique to characterize the heavy-traffic behavior of the expectation of the sum queue lengths in steady-state, under the assumption that all ports are saturated and all queues receive non-zero traffic. Under these conditions, we show that the heavy-traffic scaled queue length is given by (1−1/2n||σ||2, where σ is the vector of the standard deviations of arrivals to each port in the heavy-traffic limit. In the special case of uniform Bernoulli arrivals, the corresponding formula is given by (n−3/2+1/2n. The result shows that the heavy-traffic scaled queue length has optimal scaling with respect to n, thus settling one version of an open conjecture; in fact, it is shown that the heavy-traffic queue length is at most within a factor of two from the optimal. We then consider certain asymptotic regimes where the load of the system scales simultaneously with the number of ports. We show that the MaxWeight algorithm has optimal queue length scaling behavior provided that the arrival rate approaches capacity sufficiently fast.
Maximum Likelihood in a Generalized Linear Finite Mixture Model by Using the EM Algorithm
Jansen, R.C.
A generalized linear finite mixture model and an EM algorithm to fit the model to data are described. By this approach the finite mixture model is embedded within the general framework of generalized linear models (GLMs). Implementation of the proposed EM algorithm can be readily done in statistical
Weissman, Alexander
2013-01-01
Convergence of the expectation-maximization (EM) algorithm to a global optimum of the marginal log likelihood function for unconstrained latent variable models with categorical indicators is presented. The sufficient conditions under which global convergence of the EM algorithm is attainable are provided in an information-theoretic context by…
Cai, Li; Lee, Taehun
2009-01-01
We apply the Supplemented EM algorithm (Meng & Rubin, 1991) to address a chronic problem with the "two-stage" fitting of covariance structure models in the presence of ignorable missing data: the lack of an asymptotically chi-square distributed goodness-of-fit statistic. We show that the Supplemented EM algorithm provides a…
Directory of Open Access Journals (Sweden)
Аndriy V. Sadchenko
2015-12-01
Full Text Available Digital television systems need to ensure that all digital signals processing operations are performed simultaneously and consistently. Frame synchronization dictated by the need to match phases of transmitter and receiver so that it would be possible to identify the start of a frame. As a frame synchronization signals are often used long length binary sequence with good aperiodic autocorrelation function. Aim: This work is dedicated to the development of the algorithm of random length sequences synthesis. Materials and Methods: The paper provides a comparative analysis of the known sequences, which can be used at present as synchronization ones, revealed their advantages and disadvantages. This work proposes the algorithm for the synthesis of binary synchronization sequences of random length with good autocorrelation properties based on noise generator with a uniform distribution law of probabilities. A "white noise" semiconductor generator is proposed to use as the initial material for the synthesis of binary sequences with desired properties. Results: The statistical analysis of the initial implementations of the "white noise" and synthesized sequences for frame synchronization of digital television is conducted. The comparative analysis of the synthesized sequences with known ones was carried out. The results show the benefits of obtained sequences in compare with known ones. The performed simulations confirm the obtained results. Conclusions: Thus, the search algorithm of binary synchronization sequences with desired autocorrelation properties received. According to this algorithm, the sequence can be longer in length and without length limitations. The received sync sequence can be used for frame synchronization in modern digital communication systems that will increase their efficiency and noise immunity.
An EM algorithm for mapping segregation distortion loci.
Zhu, Chengsong; Zhang, Yuan-Ming
2007-11-29
Chromosomal region that causes distorted segregation ratios is referred to as segregation distortion locus (SDL). The distortion is caused either by differential representation of SDL genotypes in gametes before fertilization or by viability differences of SDL genotypes after fertilization but before genotype scoring. In both cases, observable phenotypes are distorted for marker loci in the chromosomal region close to the SDL. Under the quantitative genetics model for viability selection by proposing a continuous liability controlling the viability of individual, a simplex algorithm has been used to search for the solution in SDL mapping. However, they did not consider the effects of SDL on the construction of linkage maps. We proposed a multipoint maximum-likelihood method to estimate the position and the effects of SDL under the liability model together with both selection coefficients of marker genotypes and recombination fractions. The method was implemented via an expectation and maximization (EM) algorithm. The superiority of the method proposed under the liability model over the previous methods was verified by a series of Monte Carlo simulation experiments, together with a working example derived from the MAPMAKER/QTL software. Our results suggested that the new method can serve as a powerful alternative to existing methods for SDL mapping. Under the liability model, the new method can simultaneously estimate the position and the effects of SDL as well as the recombinant fractions between adjacent markers, and also be used to probe into the genetic mechanism for the bias of uncorrected map distance and to elucidate the relationship between the viability selection and genetic linkage.
An EM algorithm for mapping segregation distortion loci
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Zhang Yuan-Ming
2007-11-01
Full Text Available Abstract Background Chromosomal region that causes distorted segregation ratios is referred to as segregation distortion locus (SDL. The distortion is caused either by differential representation of SDL genotypes in gametes before fertilization or by viability differences of SDL genotypes after fertilization but before genotype scoring. In both cases, observable phenotypes are distorted for marker loci in the chromosomal region close to the SDL. Under the quantitative genetics model for viability selection by proposing a continuous liability controlling the viability of individual, a simplex algorithm has been used to search for the solution in SDL mapping. However, they did not consider the effects of SDL on the construction of linkage maps. Results We proposed a multipoint maximum-likelihood method to estimate the position and the effects of SDL under the liability model together with both selection coefficients of marker genotypes and recombination fractions. The method was implemented via an expectation and maximization (EM algorithm. The superiority of the method proposed under the liability model over the previous methods was verified by a series of Monte Carlo simulation experiments, together with a working example derived from the MAPMAKER/QTL software. Conclusion Our results suggested that the new method can serve as a powerful alternative to existing methods for SDL mapping. Under the liability model, the new method can simultaneously estimate the position and the effects of SDL as well as the recombinant fractions between adjacent markers, and also be used to probe into the genetic mechanism for the bias of uncorrected map distance and to elucidate the relationship between the viability selection and genetic linkage.
State-space models - from the EM algorithm to a gradient approach
DEFF Research Database (Denmark)
Olsson, Rasmus Kongsgaard; Petersen, Kaare Brandt; Lehn-Schiøler, Tue
2007-01-01
Slow convergence is observed in the EM algorithm for linear state-space models. We propose to circumvent the problem by applying any off-the-shelf quasi-Newton-type optimizer, which operates on the gradient of the log-likelihood function. Such an algorithm is a practical alternative due to the fact...... that the exact gradient of the log-likelihood function can be computed by recycling components of the expectation-maximization (EM) algorithm. We demonstrate the efficiency of the proposed method in three relevant instances of the linear state-space model. In high signal-to-noise ratios, where EM is particularly...
Implementing EM and Viterbi algorithms for Hidden Markov Model in linear memory
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Winters-Hilt Stephen
2008-04-01
Full Text Available Abstract Background The Baum-Welch learning procedure for Hidden Markov Models (HMMs provides a powerful tool for tailoring HMM topologies to data for use in knowledge discovery and clustering. A linear memory procedure recently proposed by Miklós, I. and Meyer, I.M. describes a memory sparse version of the Baum-Welch algorithm with modifications to the original probabilistic table topologies to make memory use independent of sequence length (and linearly dependent on state number. The original description of the technique has some errors that we amend. We then compare the corrected implementation on a variety of data sets with conventional and checkpointing implementations. Results We provide a correct recurrence relation for the emission parameter estimate and extend it to parameter estimates of the Normal distribution. To accelerate estimation of the prior state probabilities, and decrease memory use, we reverse the originally proposed forward sweep. We describe different scaling strategies necessary in all real implementations of the algorithm to prevent underflow. In this paper we also describe our approach to a linear memory implementation of the Viterbi decoding algorithm (with linearity in the sequence length, while memory use is approximately independent of state number. We demonstrate the use of the linear memory implementation on an extended Duration Hidden Markov Model (DHMM and on an HMM with a spike detection topology. Comparing the various implementations of the Baum-Welch procedure we find that the checkpointing algorithm produces the best overall tradeoff between memory use and speed. In cases where sequence length is very large (for Baum-Welch, or state number is very large (for Viterbi, the linear memory methods outlined may offer some utility. Conclusion Our performance-optimized Java implementations of Baum-Welch algorithm are available at http://logos.cs.uno.edu/~achurban. The described method and implementations will aid
Length-Bounded Hybrid CPU/GPU Pattern Matching Algorithm for Deep Packet Inspection
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Yi-Shan Lin
2017-01-01
Full Text Available Since frequent communication between applications takes place in high speed networks, deep packet inspection (DPI plays an important role in the network application awareness. The signature-based network intrusion detection system (NIDS contains a DPI technique that examines the incoming packet payloads by employing a pattern matching algorithm that dominates the overall inspection performance. Existing studies focused on implementing efficient pattern matching algorithms by parallel programming on software platforms because of the advantages of lower cost and higher scalability. Either the central processing unit (CPU or the graphic processing unit (GPU were involved. Our studies focused on designing a pattern matching algorithm based on the cooperation between both CPU and GPU. In this paper, we present an enhanced design for our previous work, a length-bounded hybrid CPU/GPU pattern matching algorithm (LHPMA. In the preliminary experiment, the performance and comparison with the previous work are displayed, and the experimental results show that the LHPMA can achieve not only effective CPU/GPU cooperation but also higher throughput than the previous method.
Word-length algorithm for language identification of under-resourced languages
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Ali Selamat
2016-10-01
Full Text Available Language identification is widely used in machine learning, text mining, information retrieval, and speech processing. Available techniques for solving the problem of language identification do require large amount of training text that are not available for under-resourced languages which form the bulk of the World’s languages. The primary objective of this study is to propose a lexicon based algorithm which is able to perform language identification using minimal training data. Because language identification is often the first step in many natural language processing tasks, it is necessary to explore techniques that will perform language identification in the shortest possible time. Hence, the second objective of this research is to study the effect of the proposed algorithm on the run-time performance of language identification. Precision, recall, and F1 measures were used to determine the effectiveness of the proposed word length algorithm using datasets drawn from the Universal Declaration of Human Rights Act in 15 languages. The experimental results show good accuracy on language identification at the document level and at the sentence level based on the available dataset. The improved algorithm also showed significant improvement in run time performance compared with the spelling checker approach.
A spatially constrained generative model and an EM algorithm for image segmentation.
Diplaros, Aristeidis; Vlassis, Nikos; Gevers, Theo
2007-05-01
In this paper, we present a novel spatially constrained generative model and an expectation-maximization (EM) algorithm for model-based image segmentation. The generative model assumes that the unobserved class labels of neighboring pixels in the image are generated by prior distributions with similar parameters, where similarity is defined by entropic quantities relating to the neighboring priors. In order to estimate model parameters from observations, we derive a spatially constrained EM algorithm that iteratively maximizes a lower bound on the data log-likelihood, where the penalty term is data-dependent. Our algorithm is very easy to implement and is similar to the standard EM algorithm for Gaussian mixtures with the main difference that the labels posteriors are "smoothed" over pixels between each E- and M-step by a standard image filter. Experiments on synthetic and real images show that our algorithm achieves competitive segmentation results compared to other Markov-based methods, and is in general faster.
Wilkins, L. C.; Wintz, P. A.
1975-01-01
Many redundancy removal algorithms employ some sort of run length code. Blocks of timing words are coded with synchronization words inserted between blocks. The probability of incorrectly reconstructing a sample because of a channel error in the timing data is a monotonically nondecreasing function of time since the last synchronization word. In this paper we compute the 'probability that the accumulated magnitude of timing errors equal zero' as a function of time since the last synchronization word for a zero-order predictor (ZOP). The result is valid for any data source that can be modeled by a first-order Markov chain and any digital channel that can be modeled by a channel transition matrix. An example is presented.
A QoS-Based Dynamic Queue Length Scheduling Algorithm in Multiantenna Heterogeneous Systems
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Verikoukis Christos
2010-01-01
Full Text Available The use of real-time delay-sensitive applications in wireless systems has significantly grown during the last years. Therefore the designers of wireless systems have faced a challenging issue to guarantee the required Quality of Service (QoS. On the other hand, the recent advances and the extensive use of multiple antennas have already been included in several commercial standards, where the multibeam opportunistic transmission beamforming strategies have been proposed to improve the performance of the wireless systems. A cross-layer-based dynamically tuned queue length scheduler is presented in this paper, for the Downlink of multiuser and multiantenna WLAN systems with heterogeneous traffic requirements. To align with modern wireless systems transmission strategies, an opportunistic scheduling algorithm is employed, while a priority to the different traffic classes is applied. A tradeoff between the maximization of the throughput of the system and the guarantee of the maximum allowed delay is obtained. Therefore, the length of the queue is dynamically adjusted to select the appropriate conditions based on the operator requirements.
A Hybrid Aggressive Space Mapping Algorithm for EM Optimization
DEFF Research Database (Denmark)
Bakr, M.; Bandler, J. W.; Georgieva, N.;
1999-01-01
We present a novel, Hybrid Aggressive Space Mapping (HASM) optimization algorithm. HASM is a hybrid approach exploiting both the Trust Region Aggressive Space Mapping (TRASM) algorithm and direct optimization. It does not assume that the final space-mapped design is the true optimal design and is...
Al-Jabr, Ahmad Ali
2013-03-01
In this paper, an finite-difference time-domain (FDTD) algorithm for simulating propagation of EM waves in anisotropic material is presented. The algorithm is based on the auxiliary differential equation and the general polarization formulation. In anisotropic materials, electric fields are coupled and elements in the permittivity tensor are, in general, multiterm dispersive. The presented algorithm resolves the field coupling using a formulation based on electric polarizations. It also offers a simple procedure for the treatment of multiterm dispersion in the FDTD scheme. The algorithm is tested by simulating wave propagation in 1-D magnetized plasma showing excellent agreement with analytical solutions. Extension of the algorithm to multidimensional structures is straightforward. The presented algorithm is efficient and simple compared to other algorithms found in the literature. © 2012 IEEE.
Directory of Open Access Journals (Sweden)
Liu Yu-Sun
2011-01-01
Full Text Available Abstract The performance of the wrap-around Viterbi decoding algorithm with finite truncation depth and fixed decoding trellis length is investigated for tail-biting convolutional codes in the mobile WiMAX standard. Upper bounds on the error probabilities induced by finite truncation depth and the uncertainty of the initial state are derived for the AWGN channel. The truncation depth and the decoding trellis length that yield negligible performance loss are obtained for all transmission rates over the Rayleigh channel using computer simulations. The results show that the circular decoding algorithm with an appropriately chosen truncation depth and a decoding trellis just a fraction longer than the original received code words can achieve almost the same performance as the optimal maximum likelihood decoding algorithm in mobile WiMAX. A rule of thumb for the values of the truncation depth and the trellis tail length is also proposed.
Use of the AIC with the EM algorithm: A demonstration of a probability model selection technique
Energy Technology Data Exchange (ETDEWEB)
Glosup, J.G.; Axelrod M.C. [Lawrence Livermore National Lab., CA (United States)
1994-11-15
The problem of discriminating between two potential probability models, a Gaussian distribution and a mixture of Gaussian distributions, is considered. The focus of our interest is a case where the models are potentially non-nested and the parameters of the mixture model are estimated through the EM algorithm. The AIC, which is frequently used as a criterion for discriminating between non-nested models, is modified to work with the EM algorithm and is shown to provide a model selection tool for this situation. A particular problem involving an infinite mixture distribution known as Middleton`s Class A model is used to demonstrate the effectiveness and limitations of this method.
A tailored ML-EM algorithm for reconstruction of truncated projection data using few view angles
Mao, Yanfei; Zeng, Gengsheng L.
2013-06-01
Dedicated cardiac single photon emission computed tomography (SPECT) systems have the advantage of high speed and sensitivity at no loss, or even a gain, in resolution. The potential drawbacks of these dedicated systems are data truncation by the small field of view (FOV) and the lack of view angles. Serious artifacts, including streaks outside the FOV and distortion in the FOV, are introduced to the reconstruction when using the traditional emission data maximum-likelihood expectation-maximization (ML-EM) algorithm to reconstruct images from the truncated data with a small number of views. In this note, we propose a tailored ML-EM algorithm to suppress the artifacts caused by data truncation and insufficient angular sampling by reducing the image updating step sizes for the pixels outside the FOV. As a consequence, the convergence speed for the pixels outside the FOV is decelerated. We applied the proposed algorithm to truncated analytical data, Monte Carlo simulation data and real emission data with different numbers of views. The computer simulation results show that the tailored ML-EM algorithm outperforms the conventional ML-EM algorithm in terms of streak artifacts and distortion suppression for reconstruction from truncated projection data with a small number of views.
Liu Yu-Sun; Tsai Yao-Yu
2011-01-01
Abstract The performance of the wrap-around Viterbi decoding algorithm with finite truncation depth and fixed decoding trellis length is investigated for tail-biting convolutional codes in the mobile WiMAX standard. Upper bounds on the error probabilities induced by finite truncation depth and the uncertainty of the initial state are derived for the AWGN channel. The truncation depth and the decoding trellis length that yield negligible performance loss are obtained for all transmission rates...
Robust Mean Change-Point Detecting through Laplace Linear Regression Using EM Algorithm
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Fengkai Yang
2014-01-01
normal distribution, we developed the expectation maximization (EM algorithm to estimate the position of mean change-point. We investigated the performance of the algorithm through different simulations, finding that our methods is robust to the distributions of errors and is effective to estimate the position of mean change-point. Finally, we applied our method to the classical Holbert data and detected a change-point.
Adachi, Kohei
2013-01-01
Rubin and Thayer ("Psychometrika," 47:69-76, 1982) proposed the EM algorithm for exploratory and confirmatory maximum likelihood factor analysis. In this paper, we prove the following fact: the EM algorithm always gives a proper solution with positive unique variances and factor correlations with absolute values that do not exceed one,…
Adachi, Kohei
2013-01-01
Rubin and Thayer ("Psychometrika," 47:69-76, 1982) proposed the EM algorithm for exploratory and confirmatory maximum likelihood factor analysis. In this paper, we prove the following fact: the EM algorithm always gives a proper solution with positive unique variances and factor correlations with absolute values that do not exceed one,…
A Hybrid Aggressive Space Mapping Algorithm for EM Optimization
DEFF Research Database (Denmark)
Bakr, Mohamed H.; Bandler, John W.; Georgieva, N.;
1999-01-01
We propose a novel hybrid aggressive space-mapping (HASM) optimization algorithm. HASM exploits both the trust-region aggressive space-mapping (TRASM) strategy and direct optimization. Severe differences between the coarse and fine models and nonuniqueness of the parameter extraction procedure ma...
An Efficient Forward-Reverse EM Algorithm for Statistical Inference in Stochastic Reaction Networks
Bayer, Christian
2016-01-06
In this work [1], we present an extension of the forward-reverse algorithm by Bayer and Schoenmakers [2] to the context of stochastic reaction networks (SRNs). We then apply this bridge-generation technique to the statistical inference problem of approximating the reaction coefficients based on discretely observed data. To this end, we introduce an efficient two-phase algorithm in which the first phase is deterministic and it is intended to provide a starting point for the second phase which is the Monte Carlo EM Algorithm.
EXTREME: an online EM algorithm for motif discovery
Quang, Daniel; Xie, Xiaohui
2014-01-01
Motivation: Identifying regulatory elements is a fundamental problem in the field of gene transcription. Motif discovery—the task of identifying the sequence preference of transcription factor proteins, which bind to these elements—is an important step in this challenge. MEME is a popular motif discovery algorithm. Unfortunately, MEME’s running time scales poorly with the size of the dataset. Experiments such as ChIP-Seq and DNase-Seq are providing a rich amount of information on the binding preference of transcription factors. MEME cannot discover motifs in data from these experiments in a practical amount of time without a compromising strategy such as discarding a majority of the sequences. Results: We present EXTREME, a motif discovery algorithm designed to find DNA-binding motifs in ChIP-Seq and DNase-Seq data. Unlike MEME, which uses the expectation-maximization algorithm for motif discovery, EXTREME uses the online expectation-maximization algorithm to discover motifs. EXTREME can discover motifs in large datasets in a practical amount of time without discarding any sequences. Using EXTREME on ChIP-Seq and DNase-Seq data, we discover many motifs, including some novel and infrequent motifs that can only be discovered by using the entire dataset. Conservation analysis of one of these novel infrequent motifs confirms that it is evolutionarily conserved and possibly functional. Availability and implementation: All source code is available at the Github repository http://github.com/uci-cbcl/EXTREME. Contact: xhx@ics.uci.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:24532725
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
This paper addresses the problems of parameter estimation of multivariable stationary stochastic systems on the basis of observed output data. The main contribution is to employ the expectation-maximisation (EM) method as a means for computation of the maximum-likelihood (ML) parameter estimation of the system. Closed form of the expectation of the studied system subjected to Gaussian distribution noise is derived and paraneter choice that maximizes the expectation is also proposed. This results in an iterative algorithm for parameter estimation and the robust algorithm implementation based on technique of QR-factorization and Cholesky factorization is also discussed. Moreover, algorithmic properties such as non-decreasing likelihood value, necessary and sufficient conditions for the algorithm to arrive at a local stationary parameter, the convergence rate and the factors affecting the convergence rate are analyzed. Simulation study shows that the proposed algorithm has attractive properties such as numerical stability, and avoidance of difficult initial conditions.
Comparison of parametric FBP and OS-EM reconstruction algorithm images for PET dynamic study
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Oda, Keiichi; Uemura, Koji; Kimura, Yuichi; Senda, Michio [Tokyo Metropolitan Inst. of Gerontology (Japan). Positron Medical Center; Toyama, Hinako; Ikoma, Yoko
2001-10-01
An ordered subsets expectation maximization (OS-EM) algorithm is used for image reconstruction to suppress image noise and to make non-negative value images. We have applied OS-EM to a digital brain phantom and to human brain {sup 18}F-FDG PET kinetic studies to generate parametric images. A 45 min dynamic scan was performed starting injection of FDG with a 2D PET scanner. The images were reconstructed with OS-EM (6 iterations, 16 subsets) and with filtered backprojection (FBP), and K1, k2 and k3 images were created by the Marquardt non-linear least squares method based on the 3-parameter kinetic model. Although the OS-EM activity images correlated fairly well with those obtained by FBP, the pixel correlations were poor for the k2 and k3 parametric images, but the plots were scattered along the line of identity and the mean values for K1, k2 and k3 obtained by OS-EM were almost equal to those by FBP. The kinetic fitting error for OS-EM was no smaller than that for FBP. The results suggest that OS-EM is not necessarily superior to FBP for creating parametric images. (author)
Fang, Jie; Ouyang, Hongjia; Shen, Liangzhong; Dougherty, Edward R; Liu, Wenbin
2014-12-01
The inference of gene regulatory networks is a core problem in systems biology. Many inference algorithms have been proposed and all suffer from false positives. In this paper, we use the minimum description length (MDL) principle to reduce the rate of false positives for best-fit algorithms. The performance of these algorithms is evaluated via two metrics: the normalized-edge Hamming distance and the steady-state distribution distance. Results for synthetic networks and a well-studied budding-yeast cell cycle network show that MDL-based filtering is more effective than filtering based on conditional mutual information (CMI). In addition, MDL-based filtering provides better inference than the MDL algorithm itself.
Li, X Y; Yang, G W; Zheng, D S; Guo, W S; Hung, W N N
2015-01-01
Genetic regulatory networks are the key to understanding biochemical systems. One condition of the genetic regulatory network under different living environments can be modeled as a synchronous Boolean network. The attractors of these Boolean networks will help biologists to identify determinant and stable factors. Existing methods identify attractors based on a random initial state or the entire state simultaneously. They cannot identify the fixed length attractors directly. The complexity of including time increases exponentially with respect to the attractor number and length of attractors. This study used the bounded model checking to quickly locate fixed length attractors. Based on the SAT solver, we propose a new algorithm for efficiently computing the fixed length attractors, which is more suitable for large Boolean networks and numerous attractors' networks. After comparison using the tool BooleNet, empirical experiments involving biochemical systems demonstrated the feasibility and efficiency of our approach.
Unsupervised classification algorithm based on EM method for polarimetric SAR images
Fernández-Michelli, J. I.; Hurtado, M.; Areta, J. A.; Muravchik, C. H.
2016-07-01
In this work we develop an iterative classification algorithm using complex Gaussian mixture models for the polarimetric complex SAR data. It is a non supervised algorithm which does not require training data or an initial set of classes. Additionally, it determines the model order from data, which allows representing data structure with minimum complexity. The algorithm consists of four steps: initialization, model selection, refinement and smoothing. After a simple initialization stage, the EM algorithm is iteratively applied in the model selection step to compute the model order and an initial classification for the refinement step. The refinement step uses Classification EM (CEM) to reach the final classification and the smoothing stage improves the results by means of non-linear filtering. The algorithm is applied to both simulated and real Single Look Complex data of the EMISAR mission and compared with the Wishart classification method. We use confusion matrix and kappa statistic to make the comparison for simulated data whose ground-truth is known. We apply Davies-Bouldin index to compare both classifications for real data. The results obtained for both types of data validate our algorithm and show that its performance is comparable to Wishart's in terms of classification quality.
Siswantyo, Sepha; Susanti, Bety Hayat
2016-02-01
Preneel-Govaerts-Vandewalle (PGV) schemes consist of 64 possible single-block-length schemes that can be used to build a hash function based on block ciphers. For those 64 schemes, Preneel claimed that 4 schemes are secure. In this paper, we apply length extension attack on those 4 secure PGV schemes which use RC5 algorithm in its basic construction to test their collision resistance property. The attack result shows that the collision occurred on those 4 secure PGV schemes. Based on the analysis, we indicate that Feistel structure and data dependent rotation operation in RC5 algorithm, XOR operations on the scheme, along with selection of additional message block value also give impact on the collision to occur.
3.5A cryoEM structure of hepatitis B virus core assembled from full-length core protein.
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Xuekui Yu
Full Text Available The capsid shell of infectious hepatitis B virus (HBV is composed of 240 copies of a single protein called HBV core antigen (HBc. An atomic model of a core assembled from truncated HBc was determined previously by X-ray crystallography. In an attempt to obtain atomic structural information of HBV core in a near native, non-crystalline environment, we reconstructed a 3.5Å-resolution structure of a recombinant core assembled from full-length HBc by cryo electron microscopy (cryoEM and derived an atomic model. The structure shows that the 240 molecules of full-length HBc form a core with two layers. The outer layer, composed of the N-terminal assembly domain, is similar to the crystal structure of the truncated HBc, but has three differences. First, unlike the crystal structure, our cryoEM structure shows no disulfide bond between the Cys61 residues of the two subunits within the dimer building block, indicating such bond is not required for core formation. Second, our cryoEM structure reveals up to four more residues in the linker region (amino acids 140-149. Third, the loops in the cryoEM structures containing this linker region in subunits B and C are oriented differently (~30° and ~90° from their counterparts in the crystal structure. The inner layer, composed of the C-terminal arginine-rich domain (ARD and the ARD-bound RNAs, is partially-ordered and connected with the outer layer through linkers positioned around the two-fold axes. Weak densities emanate from the rims of positively charged channels through the icosahedral three-fold and local three-fold axes. We attribute these densities to the exposed portions of some ARDs, thus explaining ARD's accessibility by proteases and antibodies. Our data supports a role of ARD in mediating communication between inside and outside of the core during HBV maturation and envelopment.
Directory of Open Access Journals (Sweden)
Jorge A Banda
Full Text Available To examine the effects of accelerometer epoch lengths, wear time (WT algorithms, and activity cut-points on estimates of WT, sedentary behavior (SB, and physical activity (PA.268 7-11 year-olds with BMI ≥ 85th percentile for age and sex wore accelerometers on their right hips for 4-7 days. Data were processed and analyzed at epoch lengths of 1-, 5-, 10-, 15-, 30-, and 60-seconds. For each epoch length, WT minutes/day was determined using three common WT algorithms, and minutes/day and percent time spent in SB, light (LPA, moderate (MPA, and vigorous (VPA PA were determined using five common activity cut-points. ANOVA tested differences in WT, SB, LPA, MPA, VPA, and MVPA when using the different epoch lengths, WT algorithms, and activity cut-points.WT minutes/day varied significantly by epoch length when using the NHANES WT algorithm (p < .0001, but did not vary significantly by epoch length when using the ≥ 20 minute consecutive zero or Choi WT algorithms. Minutes/day and percent time spent in SB, LPA, MPA, VPA, and MVPA varied significantly by epoch length for all sets of activity cut-points tested with all three WT algorithms (all p < .0001. Across all epoch lengths, minutes/day and percent time spent in SB, LPA, MPA, VPA, and MVPA also varied significantly across all sets of activity cut-points with all three WT algorithms (all p < .0001.The common practice of converting WT algorithms and activity cut-point definitions to match different epoch lengths may introduce significant errors. Estimates of SB and PA from studies that process and analyze data using different epoch lengths, WT algorithms, and/or activity cut-points are not comparable, potentially leading to very different results, interpretations, and conclusions, misleading research and public policy.
Directory of Open Access Journals (Sweden)
Riediger Michael L. B.
2005-01-01
Full Text Available In this paper, we consider the issue of blind detection of Alamouti-type differential space-time (ST modulation in static Rayleigh fading channels. We focus our attention on a π / 2 -shifted BPSK constellation, introducing a novel transformation to the received signal such that this binary ST modulation, which has a second-order transmit diversity, is equivalent to QPSK modulation with second-order receive diversity. This equivalent representation allows us to apply a low-complexity detection technique specifically designed for receive diversity, namely, scalar multiple-symbol differential detection (MSDD. To further increase receiver performance, we apply an iterative expectation-maximization (EM algorithm which performs joint channel estimation and sequence detection. This algorithm uses minimum mean square estimation to obtain channel estimates and the maximum-likelihood principle to detect the transmitted sequence, followed by differential decoding. With receiver complexity proportional to the observation window length, our receiver can achieve the performance of a coherent maximal ratio combining receiver (with differential decoding in as few as a single EM receiver iteration, provided that the window size of the initial MSDD is sufficiently long. To further demonstrate that the MSDD is a vital part of this receiver setup, we show that an initial ST conventional differential detector would lead to strange convergence behavior in the EM algorithm.
Model Selection Criteria for Missing-Data Problems Using the EM Algorithm.
Ibrahim, Joseph G; Zhu, Hongtu; Tang, Niansheng
2008-12-01
We consider novel methods for the computation of model selection criteria in missing-data problems based on the output of the EM algorithm. The methodology is very general and can be applied to numerous situations involving incomplete data within an EM framework, from covariates missing at random in arbitrary regression models to nonignorably missing longitudinal responses and/or covariates. Toward this goal, we develop a class of information criteria for missing-data problems, called IC(H) (,) (Q), which yields the Akaike information criterion and the Bayesian information criterion as special cases. The computation of IC(H) (,) (Q) requires an analytic approximation to a complicated function, called the H-function, along with output from the EM algorithm used in obtaining maximum likelihood estimates. The approximation to the H-function leads to a large class of information criteria, called IC(H̃) (() (k) (),) (Q). Theoretical properties of IC(H̃) (() (k) (),) (Q), including consistency, are investigated in detail. To eliminate the analytic approximation to the H-function, a computationally simpler approximation to IC(H) (,) (Q), called IC(Q), is proposed, the computation of which depends solely on the Q-function of the EM algorithm. Advantages and disadvantages of IC(H̃) (() (k) (),) (Q) and IC(Q) are discussed and examined in detail in the context of missing-data problems. Extensive simulations are given to demonstrate the methodology and examine the small-sample and large-sample performance of IC(H̃) (() (k) (),) (Q) and IC(Q) in missing-data problems. An AIDS data set also is presented to illustrate the proposed methodology.
Clustering dynamic textures with the hierarchical em algorithm for modeling video.
Mumtaz, Adeel; Coviello, Emanuele; Lanckriet, Gert R G; Chan, Antoni B
2013-07-01
Dynamic texture (DT) is a probabilistic generative model, defined over space and time, that represents a video as the output of a linear dynamical system (LDS). The DT model has been applied to a wide variety of computer vision problems, such as motion segmentation, motion classification, and video registration. In this paper, we derive a new algorithm for clustering DT models that is based on the hierarchical EM algorithm. The proposed clustering algorithm is capable of both clustering DTs and learning novel DT cluster centers that are representative of the cluster members in a manner that is consistent with the underlying generative probabilistic model of the DT. We also derive an efficient recursive algorithm for sensitivity analysis of the discrete-time Kalman smoothing filter, which is used as the basis for computing expectations in the E-step of the HEM algorithm. Finally, we demonstrate the efficacy of the clustering algorithm on several applications in motion analysis, including hierarchical motion clustering, semantic motion annotation, and learning bag-of-systems (BoS) codebooks for dynamic texture recognition.
Algorithmic analysis of the maximum level length in general-block two-dimensional Markov processes
Directory of Open Access Journals (Sweden)
2006-01-01
Full Text Available Two-dimensional continuous-time Markov chains (CTMCs are useful tools for studying stochastic models such as queueing, inventory, and production systems. Of particular interest in this paper is the distribution of the maximal level visited in a busy period because this descriptor provides an excellent measure of the system congestion. We present an algorithmic analysis for the computation of its distribution which is valid for Markov chains with general-block structure. For a multiserver batch arrival queue with retrials and negative arrivals, we exploit the underlying internal block structure and present numerical examples that reveal some interesting facts of the system.
Nonlinear Random Effects Mixture Models: Maximum Likelihood Estimation via the EM Algorithm.
Wang, Xiaoning; Schumitzky, Alan; D'Argenio, David Z
2007-08-15
Nonlinear random effects models with finite mixture structures are used to identify polymorphism in pharmacokinetic/pharmacodynamic phenotypes. An EM algorithm for maximum likelihood estimation approach is developed and uses sampling-based methods to implement the expectation step, that results in an analytically tractable maximization step. A benefit of the approach is that no model linearization is performed and the estimation precision can be arbitrarily controlled by the sampling process. A detailed simulation study illustrates the feasibility of the estimation approach and evaluates its performance. Applications of the proposed nonlinear random effects mixture model approach to other population pharmacokinetic/pharmacodynamic problems will be of interest for future investigation.
Finite sample performance of the E-M algorithm for ranks data modelling
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Angela D'Elia
2007-10-01
Full Text Available We check the finite sample performance of the maximum likelihood estimators of the parameters of a mixture distribution recently introduced for modelling ranks/preference data. The estimates are derived by the E-M algorithm and the performance is evaluated both from an univariate and bivariate points of view. While the results are generally acceptable as far as it concerns the bias, the Monte Carlo experiment shows a different behaviour of the estimators efficiency for the two parameters of the mixture, mainly depending upon their location in the admissible parametric space. Some operative suggestions conclude the paer.
Directory of Open Access Journals (Sweden)
Offmann Bernard
2008-05-01
Full Text Available Abstract Background Distantly related proteins adopt and retain similar structural scaffolds despite length variations that could be as much as two-fold in some protein superfamilies. In this paper, we describe an analysis of indel regions that accommodate length variations amongst related proteins. We have developed an algorithm CUSP, to examine multi-membered PASS2 superfamily alignments to identify indel regions in an automated manner. Further, we have used the method to characterize the length, structural type and biochemical features of indels in related protein domains. Results CUSP, examines protein domain structural alignments to distinguish regions of conserved structure common to related proteins from structurally unconserved regions that vary in length and type of structure. On a non-redundant dataset of 353 domain superfamily alignments from PASS2, we find that 'length- deviant' protein superfamilies show > 30% length variation from their average domain length. 60% of additional lengths that occur in indels are short-length structures ( 15 residues in length. Structural types in indels also show class-specific trends. Conclusion The extent of length variation varies across different superfamilies and indels show class-specific trends for preferred lengths and structural types. Such indels of different lengths even within a single protein domain superfamily could have structural and functional consequences that drive their selection, underlying their importance in similarity detection and computational modelling. The availability of systematic algorithms, like CUSP, should enable decision making in a domain superfamily-specific manner.
Shepherd, Ross K; Meuwissen, Theo H E; Woolliams, John A
2010-10-22
The information provided by dense genome-wide markers using high throughput technology is of considerable potential in human disease studies and livestock breeding programs. Genome-wide association studies relate individual single nucleotide polymorphisms (SNP) from dense SNP panels to individual measurements of complex traits, with the underlying assumption being that any association is caused by linkage disequilibrium (LD) between SNP and quantitative trait loci (QTL) affecting the trait. Often SNP are in genomic regions of no trait variation. Whole genome Bayesian models are an effective way of incorporating this and other important prior information into modelling. However a full Bayesian analysis is often not feasible due to the large computational time involved. This article proposes an expectation-maximization (EM) algorithm called emBayesB which allows only a proportion of SNP to be in LD with QTL and incorporates prior information about the distribution of SNP effects. The posterior probability of being in LD with at least one QTL is calculated for each SNP along with estimates of the hyperparameters for the mixture prior. A simulated example of genomic selection from an international workshop is used to demonstrate the features of the EM algorithm. The accuracy of prediction is comparable to a full Bayesian analysis but the EM algorithm is considerably faster. The EM algorithm was accurate in locating QTL which explained more than 1% of the total genetic variation. A computational algorithm for very large SNP panels is described. emBayesB is a fast and accurate EM algorithm for implementing genomic selection and predicting complex traits by mapping QTL in genome-wide dense SNP marker data. Its accuracy is similar to Bayesian methods but it takes only a fraction of the time.
Maximum-Likelihood Semiblind Equalization of Doubly Selective Channels Using the EM Algorithm
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Gideon Kutz
2010-01-01
Full Text Available Maximum-likelihood semi-blind joint channel estimation and equalization for doubly selective channels and single-carrier systems is proposed. We model the doubly selective channel as an FIR filter where each filter tap is modeled as a linear combination of basis functions. This channel description is then integrated in an iterative scheme based on the expectation-maximization (EM principle that converges to the channel description vector estimation. We discuss the selection of the basis functions and compare various functions sets. To alleviate the problem of convergence to a local maximum, we propose an initialization scheme to the EM iterations based on a small number of pilot symbols. We further derive a pilot positioning scheme targeted to reduce the probability of convergence to a local maximum. Our pilot positioning analysis reveals that for high Doppler rates it is better to spread the pilots evenly throughout the data block (and not to group them even for frequency-selective channels. The resulting equalization algorithm is shown to be superior over previously proposed equalization schemes and to perform in many cases close to the maximum-likelihood equalizer with perfect channel knowledge. Our proposed method is also suitable for coded systems and as a building block for Turbo equalization algorithms.
Indian Academy of Sciences (India)
Saurabh Ghosh; Partha P. Majumder
2000-08-01
Mapping a locus controlling a quantitative genetic trait (e.g. blood pressure) to a specific genomic region is of considerable contemporary interest. Data on the quantitative trait under consideration and several codominant genetic markers with known genomic locations are collected from members of families and statistically analysed to estimate the recombination fraction, , between the putative quantitative trait locus and a genetic marker. One of the major complications in estimating for a quantitative trait in humans is the lack of haplotype information on members of families. We have devised a computationally simple two-stage method of estimation of in the absence of haplotypic information using the expectation-maximization (EM) algorithm. In the first stage, parameters of the quantitative trait locus (QTL) are estimated on the basis of data of a sample of unrelated individuals and a Bayes's rule is used to classify each parent into a QTL genotypic class. In the second stage, we have proposed an EM algorithm for obtaining the maximum-likelihood estimate of based on data of informative families (which are identified upon inferring parental QTL genotypes performed in the first stage). The purpose of this paper is to investigate whether, instead of using genotypically `classified' data of parents, the use of posterior probabilities of QT genotypes of parents at the second stage yields better estimators. We show, using simulated data, that the proposed procedure using posterior probabilities is statistically more efficient than our earlier classification procedure, although it is computationally heavier.
A pathway EM-algorithm for estimating vaccine efficacy with a non-monotone validation set.
Yang, Yang; Halloran, M Elizabeth; Chen, Yanjun; Kenah, Eben
2014-09-01
Here, we consider time-to-event data where individuals can experience two or more types of events that are not distinguishable from one another without further confirmation, perhaps by laboratory test. The event type of primary interest can occur only once. The other types of events can recur. If the type of a portion of the events is identified, this forms a validation set. However, even if a random sample of events are tested, confirmations can be missing nonmonotonically, creating uncertainty about whether an individual is still at risk for the event of interest. For example, in a study to estimate efficacy of an influenza vaccine, an individual may experience a sequence of symptomatic respiratory illnesses caused by various pathogens over the season. Often only a limited number of these episodes are confirmed in the laboratory to be influenza-related or not. We propose two novel methods to estimate covariate effects in this survival setting, and subsequently vaccine efficacy. The first is a pathway expectation-maximization (EM) algorithm that takes into account all pathways of event types in an individual compatible with that individual's test outcomes. The pathway EM iteratively estimates baseline hazards that are used to weight possible event types. The second method is a non-iterative pathway piecewise validation method that does not estimate the baseline hazards. These methods are compared with a previous simpler method. Simulation studies suggest mean squared error is lower in the efficacy estimates when the baseline hazards are estimated, especially at higher hazard rates. We use the pathway EM-algorithm to reevaluate the efficacy of a trivalent live-attenuated influenza vaccine during the 2003-2004 influenza season in Temple-Belton, Texas, and compare our results with a previously published analysis. © 2014, The International Biometric Society.
A structural dynamic factor model for the effects of monetary policy estimated by the EM algorithm
DEFF Research Database (Denmark)
Bork, Lasse
This paper applies the maximum likelihood based EM algorithm to a large-dimensional factor analysis of US monetary policy. Specifically, economy-wide effects of shocks to the US federal funds rate are estimated in a structural dynamic factor model in which 100+ US macroeconomic and financial time...... series are driven by the joint dynamics of the federal funds rate and a few correlated dynamic factors. This paper contains a number of methodological contributions to the existing literature on data-rich monetary policy analysis. Firstly, the identification scheme allows for correlated factor dynamics...... as opposed to the orthogonal factors resulting from the popular principal component approach to structural factor models. Correlated factors are economically more sensible and important for a richer monetary policy transmission mechanism. Secondly, I consider both static factor loadings as well as dynamic...
Discriminative variable selection for clustering with the sparse Fisher-EM algorithm
Bouveyron, Charles
2012-01-01
The interest in variable selection for clustering has increased recently due to the growing need in clustering high-dimensional data. Variable selection allows in particular to ease both the clustering and the interpretation of the results. Existing approaches have demonstrated the efficiency of variable selection for clustering but turn out to be either very time consuming or not sparse enough in high-dimensional spaces. This work proposes to perform a selection of the discriminative variables by introducing sparsity in the loading matrix of the Fisher-EM algorithm. This clustering method has been recently proposed for the simultaneous visualization and clustering of high-dimensional data. It is based on a latent mixture model which fits the data into a low-dimensional discriminative subspace. Three different approaches are proposed in this work to introduce sparsity in the orientation matrix of the discriminative subspace through $\\ell_{1}$-type penalizations. Experimental comparisons with existing approach...
A structural dynamic factor model for the effects of monetary policy estimated by the EM algorithm
DEFF Research Database (Denmark)
Bork, Lasse
This paper applies the maximum likelihood based EM algorithm to a large-dimensional factor analysis of US monetary policy. Specifically, economy-wide effects of shocks to the US federal funds rate are estimated in a structural dynamic factor model in which 100+ US macroeconomic and financial time...... series are driven by the joint dynamics of the federal funds rate and a few correlated dynamic factors. This paper contains a number of methodological contributions to the existing literature on data-rich monetary policy analysis. Firstly, the identification scheme allows for correlated factor dynamics...... as opposed to the orthogonal factors resulting from the popular principal component approach to structural factor models. Correlated factors are economically more sensible and important for a richer monetary policy transmission mechanism. Secondly, I consider both static factor loadings as well as dynamic...
An R function for imputation of missing cells in two-way data sets by EM-AMMI algorithm
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Jakub Paderewski
2014-06-01
Full Text Available Various statistical methods for two-way classification data sets (including AMMI or GGE analyses, used in crop science for interpreting genotype-by-environment interaction require the data to be complete, that is, not to have missing cells. If there are such, however, one might impute the missing cells. The paper offers R code for imputing missing values by the EM-AMMI algorithm. In addition, a function to check the repeatability of this algorithm is proposed. This function could be used to evaluate if the missing data were imputed reliably (unambiguously, which is important especially for small data sets
Sá, Ana Cravo; Coelho, Carina Marques; Monsanto, Fátima
2014-01-01
Objectivo do estudo: comparar o desempenho dos algoritmos Pencil Beam Convolution (PBC) e do Analytical Anisotropic Algorithm (AAA) no planeamento do tratamento de tumores de mama com radioterapia conformacional a 3D.
DEFF Research Database (Denmark)
Kamchevska, Valerija; Cristofori, Valentina; Da Ros, Francesco
2016-01-01
We propose and demonstrate an algorithm that allows for automatic synchronization of SDN-controlled all-optical TDM switching nodes connected in a ring network. We experimentally show successful WDM-SDM transmission of data bursts between all ring nodes.......We propose and demonstrate an algorithm that allows for automatic synchronization of SDN-controlled all-optical TDM switching nodes connected in a ring network. We experimentally show successful WDM-SDM transmission of data bursts between all ring nodes....
Han, Miaomiao; Guo, Zhirong; Liu, Haifeng; Li, Qinghua
2017-07-01
This paper studies the influence of different path length computation models and iterative reconstruction algorithms on the quality of transmission reconstruction in Tomographic Gamma Scanning. The research purpose is to quantify and to localize heterogeneous matrices while investigating the recovery of linear attenuation coefficients (LACs) maps in 200 liter drums. Two different path length computation models so called ;point to point (PP); model and ;point to detector (PD); model are coupled with two different transmission reconstruction algorithms - Algebraic Reconstruction Technique (ART) with non-negativity constraint, and Maximum Likelihood Expectation Maximization (MLEM), respectively. Thus 4 modes are formed: ART-PP, ART-PD, MLEM-PP, MLEM-PD. The inter-comparison of transmission reconstruction qualities of these 4 modes is taken into account for heterogeneous matrices in the radioactive waste drums. Results illustrate that transmission-reconstructed qualities of MLEM algorithm are better than ART algorithm to get the most accurate LACs maps in good agreement with the reference data simulated by Monte Carlo. Moreover, PD model can be used to assay higher density waste drum and has a greater scope of application than PP model in TGS.
EM-CDKF algorithm and its applications on SINS′initial alignment%EM-CDKF算法及其SINS初始对准应用
Institute of Scientific and Technical Information of China (English)
丁国强; 徐洁; 周卫东; 张志艳
2014-01-01
针对非线性捷联惯导系统噪声先验统计信息未知问题，基于中心差分卡尔曼滤波基本算法，采用极大似然准则构造极大期望最速下降梯度算法展开系统未知噪声统计特性在线估计计算研究，构建一类捷联惯导系统初始对准极大期望自适应中心差分最优滤波算法。该算法利用极大似然准则构造系统噪声统计特性对数似然函数，采用极大期望最速下降梯度法把系统噪声统计特性估计转化为对数似然函数期望最大值计算，获得系统过程噪声和观测噪声在线递推估计的自适应极大期望中心差分卡尔曼算法。经过大方位失准角捷联惯导系统初始对准仿真实验，与中心差分卡尔曼滤波基本算法相比，自适应极大期望中心差分卡尔曼算法能够有效解决基本算法在系统噪声先验知识未知情形下的滤波精度下降甚至发散问题，并且能够实现系统噪声统计特性的在线递推估计。%As the unknow n priori statistical properties of the nonlinear strap-dow n inertial navigation system (SINS) noises ,based on the central divided Kalman filtering (CDKF) algorithm ,the expecta-tion maximum steepest descent method was presented to develop the adaptive expectation maximum based central divided Kalman filtering (EM-CDKF) algorithm with maximum likelihood criterion ,to evaluate on-line the system noise’s statistical properties .The EM-CDKF algorithm constructs the Log-likelihood function of system noises statistical properties with maximum likelihood criterion ,and transforms the estimation evaluation of system noise statistical properties into the maximum evalua-tion of Log-likelihood function with the expectation maximum steepest descent method ,and with the EM-CDKF algorithm ,the process and measurement noises can be evaluated by online recursive pat-tern .T he simulink experiments of SINS’ large azimuth misalignment angle indicate that ,compared to
Directory of Open Access Journals (Sweden)
Gallo A. S.
2005-01-01
Full Text Available We investigate the application of the Bayesian expectation-maximization (BEM technique to the design of soft-in soft-out (SISO detection algorithms for wireless communication systems operating over channels affected by parametric uncertainty. First, the BEM algorithm is described in detail and its relationship with the well-known expectation-maximization (EM technique is explained. Then, some of its applications are illustrated. In particular, the problems of SISO detection of spread spectrum, single-carrier and multicarrier space-time block coded signals are analyzed. Numerical results show that BEM-based detectors perform closely to the maximum likelihood (ML receivers endowed with perfect channel state information as long as channel variations are not too fast.
Langlois, Robert; Frank, Joachim
2011-09-01
Many cyro-EM datasets are heterogeneous stemming from molecules undergoing conformational changes. The need to characterize each of the substrates with sufficient resolution entails a large increase in the data flow and motivates the development of more effective automated particle selection algorithms. Concepts and procedures from the machine-learning field are increasingly employed toward this end. However, a review of recent literature has revealed a discrepancy in terminology of the performance scores used to compare particle selection algorithms, and this has subsequently led to ambiguities in the meaning of claimed performance. In an attempt to curtail the perpetuation of this confusion and to disentangle past mistakes, we review the performance of published particle selection efforts with a set of explicitly defined performance scores using the terminology established and accepted within the field of machine learning. Copyright © 2011 Elsevier Inc. All rights reserved.
两种改进的变步长MPPT算法性能对比研究%Comparison research of two improved variable step length MPPT algorithm
Institute of Scientific and Technical Information of China (English)
潘逸菎; 窦伟
2016-01-01
Photovoltaic array maximum power point tracking technology is one of the key technologies of the appli-cation of photovoltaic power generation.In this paper, based on the academic research, the variable step length in-cremental conductance algorithm and the perturbation and observation algorithm MPPT technologies which are the most practical application algorithm were optimized and the advantages and disadvantages are compared in detail. Comparing the results of simulations and experiments, the improved perturbation and observation algorithm could be more accurately and faster track the maximum power point, and is more suitable for the actual product.%光伏阵列最大功率点跟踪(MPPT)技术是光伏发电应用的关键技术之一.本文基于近年来学界研究成果,对实际应用最多的变步长电导增量法和扰动观察法两种MPPT技术进行优化设计,并详细对比验证了两种改进方法特性.对比仿真和实验结果表明,改进算法均能快速准确地实现最大功率跟踪,其中改进的扰动观察法因算法简单更适合实际产品使用.
Park, Sun-Youp; Choi, Jin; Roh, Dong-Goo; Park, Maru; Jo, Jung Hyun; Yim, Hong-Suh; Park, Young-Sik; Bae, Young-Ho; Park, Jang-Hyun; Moon, Hong-Kyu; Choi, Young-Jun; Cho, Sungki; Choi, Eun-Jung
2016-09-01
As described in the previous paper (Park et al. 2013), the detector subsystem of optical wide-field patrol (OWL) provides many observational data points of a single artificial satellite or space debris in the form of small streaks, using a chopper system and a time tagger. The position and the corresponding time data are matched assuming that the length of a streak on the CCD frame is proportional to the time duration of the exposure during which the chopper blades do not obscure the CCD window. In the previous study, however, the length was measured using the diagonal of the rectangle of the image area containing the streak; the results were quite ambiguous and inaccurate, allowing possible matching error of positions and time data. Furthermore, because only one (position, time) data point is created from one streak, the efficiency of the observation decreases. To define the length of a streak correctly, it is important to locate the endpoints of a streak. In this paper, a method using a differential convolution mask pattern is tested. This method can be used to obtain the positions where the pixel values are changed sharply. These endpoints can be regarded as directly detected positional data, and the number of data points is doubled by this result.
利用循环卷积实现的素长度DCT快速算法%Fast Algorithm for Computing Prime-Length DCT Using Cyclic Convolutions
Institute of Scientific and Technical Information of China (English)
殷瑞祥
2001-01-01
A new algorithm for the computation of discrete cosine transform(DCT) with odd prime length using cyclic or skew cyclic convolutions is proposed.The algorithm separates DCT coefficients into three parts: DC coefficients, evenand odd-indexed DCT coefficients. According to the number theory a new indexmapping operation is defined. By means of the index-mapping operation,the evenindexed part is converted to a cyclic convolution, and the odd-indexed part is converted to a cyclic or skew cyclic convolution depending on its length. Since efficient and fast cyclic convolution algorithms are available, the algorithm has low computational complexity, simple and regular structure.%提出了一种利用循环卷积 (Cyclicconvolution) 和扭循环卷积 (Skewcyclicconvolution) 实现计算奇素长度离散余弦变换 (DCT) 的快速新算法。算法将 DCT 系数分成三部分： 分量、偶下标 分量和奇下标分量。根据数论理论，本文定义了一种新的下标变换算子，利用该算子进行下标变换，将偶下标DCT系数的计算转化为一个循环卷积，根据不同长度，奇下标DCT系数的计算被转化为循环卷积或扭循环卷积。利用循环卷积和扭循环卷积的高效率和规则的算法，构造具有简单、规则的结构和较低的运算复杂性的奇素长度DCT快速算法。
Institute of Scientific and Technical Information of China (English)
蒋海昆; 侯海峰; 周焕鹏; 周翠英
2004-01-01
The Region-Time-Length Algorithm (RTL algorithm) is introduced and improved in the paper. Compared with the original definition, the influence of rupture length on RTL function is emphasized and the weights of epicentral distance function, time function, and rupture length function are ensured to be equal. The retrospective examinations of RTL algorithm in North China have indicated that the anomalies obtained by the improved RTL algorithm show the short or intermediate-short term precursory features in most cases. There are two types of RTL anomalous patterns before the main shock. For the Ⅰ-type, the variation pattern of the VRTL, numerical values of the VRTL(x,y, z, t) function, is complete and most of them have shown the changing pattern of "rising from 0 → turning →dropping" or "dropping from 0 → turning → rising". For the Ⅱ-type, the variation pattern of VRTL is not complete,which increases or decreases quickly from 0 and there is no evident turning, the main shock generally occurs in the short period around the peak VRTL. The rising of VRTL indicates an increase of seismic activity relative to the background level, which means the enhancement of seismic activity, while the dropping of VRTL indicates the decrease of seismic activity relative to the background level, which represents the seismic quiescence to a certain extent.According to statistical examination results of RTL algorithm in North China, the methods to distinguish the intermediate and short-term anomalies and to estimate the occurrence time of the coming main shock are given in the paper. For both Ⅰ and Ⅱ-type RTL anomalies, the R-value, i.e., the forecasting score, is about 0.6 and 0.3 for the 3months forecasting period and about 0.7 and 0.4 for the 6 months forecasting period. The preliminary discussion is also made for the influences of characteristic time-span to, characteristic distance r0, and threshold magnitude Mo on computation of VRTL, as well as some other significant
DEFF Research Database (Denmark)
Mertens, Kenneth; Ribeiro, Sofia; Ilham, Bouimetarhan
2009-01-01
A biometrical analysis of the dinoflagellate cyst Lingulodinium machaerophorum [Deflandre, G., Cookson, I.C., 1955. Fossil microplankton from Australia late Mesozoic and Tertiary sediments. Australian journal of Marine and Freshwater Research 6: 242–313.] Wall, 1967 in 144 globally distributed......, albeit with caution. The particular ecological window can be associated with known distributions of the corresponding motile stage Lingulodinium polyedrum (Stein) Dodge, 1989. Confocal laser microscopy showed that the average process length is positively related to the average distance between process...
Energy Technology Data Exchange (ETDEWEB)
Gonzaga, Adilson [Sao Paulo Univ., Sao Carlos, SP (Brazil). Escola de Engenharia. Dept. de Engenharia Eletrica; Franca, Celso Aparecido de [Sao Paulo Univ., SP (Brazil). Inst. de Fisica. Dept. de Fisica e Informatica
1996-12-31
Edge detecting techniques applied to radiographic digital images are discussed. Some algorithms have been implemented and the results are displayed to enhance boundary or hide details. An algorithm applied in a pre processed image with contrast enhanced is proposed and the results are discussed 5 refs., 4 figs.
Description and comparison of algorithms for correcting anisotropic magnification in cryo-EM images
Zhao, Jianhua; Benlekbir, Samir; Rubinstein, John L
2015-01-01
Single particle electron cryomicroscopy (cryo-EM) allows for structures of proteins and protein complexes to be determined from images of non-crystalline specimens. Cryo-EM data analysis requires electron microscope images of randomly oriented ice-embedded protein particles to be rotated and translated to allow for coherent averaging when calculating three-dimensional (3-D) structures. Rotation of 2-D images is usually done with the assumption that the magnification of the electron microscope is the same in all directions, a condition that has been found to be untrue with some electron microscopes when used with the settings necessary for cryo-EM with a direct detector device (DDD) camera (Grant and Grigorieff, in preparation). Correction of images by linear interpolation in real space has allowed high-resolution structures to be calculated from cryo-EM images for symmetric particles (Grant and Grigorieff, in preparation). Here we describe and compare a simple real space method and a somewhat more sophisticat...
A Local Scalable Distributed EM Algorithm for Large P2P Networks
National Aeronautics and Space Administration — his paper describes a local and distributed expectation maximization algorithm for learning parameters of Gaussian mixture models (GMM) in large peer-to-peer (P2P)...
Directory of Open Access Journals (Sweden)
Ying-Chih Lai
2016-05-01
Full Text Available The demand for pedestrian navigation has increased along with the rapid progress in mobile and wearable devices. This study develops an accurate and usable Step Length Estimation (SLE method for a Pedestrian Dead Reckoning (PDR system with features including a wide range of step lengths, a self-contained system, and real-time computing, based on the multi-sensor fusion and Fuzzy Logic (FL algorithms. The wide-range SLE developed in this study was achieved by using a knowledge-based method to model the walking patterns of the user. The input variables of the FL are step strength and frequency, and the output is the estimated step length. Moreover, a waist-mounted sensor module has been developed using low-cost inertial sensors. Since low-cost sensors suffer from various errors, a calibration procedure has been utilized to improve accuracy. The proposed PDR scheme in this study demonstrates its ability to be implemented on waist-mounted devices in real time and is suitable for the indoor and outdoor environments considered in this study without the need for map information or any pre-installed infrastructure. The experiment results show that the maximum distance error was within 1.2% of 116.51 m in an indoor environment and was 1.78% of 385.2 m in an outdoor environment.
Algoritmo genético em química Genetic algorithm in Chemistry
Directory of Open Access Journals (Sweden)
Paulo Augusto da Costa Filho
1999-06-01
Full Text Available Genetic algorithm is an optimization technique based on Darwin evolution theory. In last years its application in chemistry is increasing significantly due the special characteristics for optimization of complex systems. The basic principles and some further modifications implemented to improve its performance are presented, as well as a historical development. A numerical example of a function optimization is also shown to demonstrate how the algorithm works in an optimization process. Finally several chemistry applications realized until now is commented to serve as parameter to future applications in this field.
Numerical Stability Improvements for the Pseudo-Spectral EM PIC Algorithm
Godfrey, Brendan B; Haber, Irving
2013-01-01
The pseudo-spectral analytical time-domain (PSATD) particle-in-cell (PIC) algorithm solves the vacuum Maxwell's equations exactly, has no Courant time-step limit (as conventionally defined), and offers substantial flexibility in plasma and particle beam simulations. It is, however, not free of the usual numerical instabilities, including the numerical Cherenkov instability, when applied to relativistic beam simulations. This paper presents several approaches that, when combined with digital filtering, almost completely eliminate the numerical Cherenkov instability. The paper also investigates the numerical stability of the PSATD algorithm at low beam energies.
DEFF Research Database (Denmark)
Christensen, Lars P.B.; Larsen, Jan
2006-01-01
A general Variational Bayesian framework for iterative data and parameter estimation for coherent detection is introduced as a generalization of the EM-algorithm. Explicit solutions are given for MIMO channel estimation with Gaussian prior and noise covariance estimation with inverse-Wishart prio...
Multiscale Unsupervised Segmentation of SAR Imagery Using the Genetic Algorithm.
Wen, Xian-Bin; Zhang, Hua; Jiang, Ze-Tao
2008-03-12
A valid unsupervised and multiscale segmentation of synthetic aperture radar(SAR) imagery is proposed by a combination GA-EM of the Expectation Maximization(EM) algorith with the genetic algorithm (GA). The mixture multiscale autoregressive(MMAR) model is introduced to characterize and exploit the scale-to-scale statisticalvariations and statistical variations in the same scale in SAR imagery due to radar speckle,and a segmentation method is given by combining the GA algorithm with the EMalgorithm. This algorithm is capable of selecting the number of components of the modelusing the minimum description length (MDL) criterion. Our approach benefits from theproperties of the Genetic and the EM algorithm by combination of both into a singleprocedure. The population-based stochastic search of the genetic algorithm (GA) exploresthe search space more thoroughly than the EM method. Therefore, our algorithm enablesescaping from local optimal solutions since the algorithm becomes less sensitive to itsinitialization. Some experiment results are given based on our proposed approach, andcompared to that of the EM algorithms. The experiments on the SAR images show that theGA-EM outperforms the EM method.
Multiscale Unsupervised Segmentation of SAR Imagery Using the Genetic Algorithm
Directory of Open Access Journals (Sweden)
Ze-Tao Jiang
2008-03-01
Full Text Available A valid unsupervised and multiscale segmentation of synthetic aperture radar(SAR imagery is proposed by a combination GA-EM of the Expectation Maximization(EM algorith with the genetic algorithm (GA. The mixture multiscale autoregressive(MMAR model is introduced to characterize and exploit the scale-to-scale statisticalvariations and statistical variations in the same scale in SAR imagery due to radar speckle,and a segmentation method is given by combining the GA algorithm with the EMalgorithm. This algorithm is capable of selecting the number of components of the modelusing the minimum description length (MDL criterion. Our approach benefits from theproperties of the Genetic and the EM algorithm by combination of both into a singleprocedure. The population-based stochastic search of the genetic algorithm (GA exploresthe search space more thoroughly than the EM method. Therefore, our algorithm enablesescaping from local optimal solutions since the algorithm becomes less sensitive to itsinitialization. Some experiment results are given based on our proposed approach, andcompared to that of the EM algorithms. The experiments on the SAR images show that theGA-EM outperforms the EM method.
Institute of Scientific and Technical Information of China (English)
CHEN Fei; LUO Lin; JIN Yaqiu
2004-01-01
To automatically detect and analyze the surface change in the urban area from multi-temporal SAR images, an algorithm of two-threshold expectation maximum (EM) and Markov random field (MRF) is developed. Difference of the SAR images demonstrates variation of backscattering caused by the surface change all over the image pixels. Two thresholds are obtained by the EM iterative process and categorized to three classes: enhanced scattering, reduced scattering and unchanged regimes. Initializing from the EM result, the iterated conditional modes (ICM) algorithm of the MRF is then used to analyze the detection of contexture change in the urban area. As an example, two images of the ERS-2 SAR in 1996 and 2002 over the Shanghai City are studied.
An Algorithm for Recognition of Turbo Code Length Based on Matrix Analysis%一种基于矩阵分析的Turbo码长识别算法
Institute of Scientific and Technical Information of China (English)
李啸天; 李艳斌; 昝俊军; 杜宇峰
2012-01-01
Aiming at the recognition of turbo codes in information interception,an algorithm for recognition of turbo code length based on matrix analysis is prop osed.The basic principle of turbo codes on trellis termination is presented fir stly,and then with an in-deep study on the first,second,third way＇s and the whole generator matrix,turbo codes on trellis termination are definite to be li near block codes.The recognition method of linear block codes is introduced to turbo codes,and the algorithm is improved.Simulation experiment shows the good performance of this algorithm at high BER.%针对信息截获领域中Turbo码识别问题,提出了一种基于矩阵分析的Turbo码长识别算法。简述了Turbo码编码和归零的基本原理,深入分析了Turbo码第1路、第2路、第3路和整体的生成矩阵,得出其本质上是一种线性分组码。将线性分组码的码长识别方法引入到Turbo码识别当中,并对算法进行了改进。仿真实验表明,此方法在较高的误码率基础上有着良好的识别效果。
考虑展宽段的路段排队长度检测算法%Road Queue Length Detection Algorithm Considering Stretching Segment
Institute of Scientific and Technical Information of China (English)
杨雷; 吕鹏
2012-01-01
为了实时估计路段车辆排队长度,利用铺设在路段上的检测器,提出了一种车辆排队估计方法,对车辆排队进行实时跟踪.该方法考虑了一般的道路拓扑结构,路段排队的演化过程分为四个阶段:初始排队阶段、排队蔓延阶段、排队上溯阶段和堵塞路段阶段,不同阶段的排队利用不同的信息,通过不同的模型进行推算,通过实地调查验证,可以高效实时追踪路段排队的演化.%In order to estimate real-time queue length and provide information for traffic management, an algorithm was proposed. This method uses detector lay under road surface to track vehicle queue. General road topology was considered. Queue evolution was divided into four stages: initial queue stage, queue propagation stage, queue spillover stage, and fully congested stage. Different information was used to estimate queue length in different stages. The field test proves the effectiveness of the method.
基于位长四叉树的EZBC改进算法%An improved EZBC algorithm based on bit-length quadtree
Institute of Scientific and Technical Information of China (English)
王仁龙; 阮双琛; 刘承香; 陈俊伟
2012-01-01
基于位长四叉树结构,提出一种嵌入零块和上下文模型的图像编码( embedded zeroblock coding and context modeling,EZBC)改进算法,其仅利用位长四叉树就可以完成编码,并形成算术编码器所需的上下文,不仅可以获得与EZBC算法基本一致的压缩性能,且相对EZBC算法可节约90％的内存.通过位长四叉树对小波系数进行快速定位和重要性判断,不再采用链表操作,加快了编码速度,有利于算法的硬件实现.%An improved embedded zeroblock coding ( EZBC ) and context modeling algorithm based on a bit length quadtree is proposed in this paper- The bit length quadtree is used to complete the coding process and create the output context for Arithmetic Coder.The same performance of compression is achieved as EZBC while the memory used during encoding decreased by more than 90% compared to that required in EZBC. The bit length quadtree can be used to quickly determine the location of the wavelet coefficients and their significance instead of the linked lists usually used in EZBC.The encoding speed is significantly increased,which is helpfui for its hardware implementation.
NURBS curve discrete algorithm based on equal arc-length principle%等弧长原则的NURBS曲线离散算法
Institute of Scientific and Technical Information of China (English)
贾春阳; 杨岳; 陈峰
2014-01-01
NURBS曲线广泛应用于工业产品复杂曲线曲面设计中，但在实际应用中常遇到曲线离散的几何处理问题。针对NURBS曲线离散问题，提出了一种按等弧长原则对NURBS曲线进行离散的方法。该方法引入步长函数控制离散曲线段的弧长，采用积分法和迭代法调整步长函数以控制曲线的离散精度，通过误差检验方法校验曲线离散的逼近精度。通过实际算例，验证了NURBS曲线等弧长离散算法的合理性和有效性。%NURBS curves are widely used in complex curves and curved surfaces of industrial product design, but geometry processing problems of curve discrete are found in practical applications. According to the NURBS curve discrete problems, a method of curve discrete based on equal arc-length principle is put forward. Step function is introduced to control the length of the discrete curve, and the precision of curve discrete can be controlled by adjusting step function through integration and itera-tive methods. The approximation accuracy of curve division is checked by error checking algorithm. The rationality and validity of the NURBS curve discrete based on equal arc-length principle are verified by practical calculation example.
Suppression of EM Fields using Active Control Algorithms and MIMO Antenna System
Directory of Open Access Journals (Sweden)
A. Mohammed
2004-09-01
Full Text Available Active methods for attenuating acoustic pressure fields have beensuccessfully used in many applications. In this paper we investigatesome of these active control methods in combination with a MIMO antennasystem in order to assess their validity and performance when appliedto electromagnetic fields. The application that we evaluated in thispaper is a model of a mobile phone equipped with one ordinarytransmitting antenna and two actuator-antennas which purpose is toreduce the electromagnetic field at a specific area in space (e.g. atthe human head. Simulation results show the promise of using theadaptive active control algorithms and MIMO system to attenuate theelectromagnetic field power density.
Directory of Open Access Journals (Sweden)
Geoff McLachlan
2013-11-01
The usefulness of the proposed algorithm is demonstrated in three applications to real datasets. The first example illustrates the use of the main function fmmst in the package by fitting a MST distribution to a bivariate unimodal flow cytometric sample. The second example fits a mixture of MST distributions to the Australian Institute of Sport (AIS data, and demonstrates that EMMIXuskew can provide better clustering results than mixtures with restricted MST components. In the third example, EMMIXuskew is applied to classify cells in a trivariate flow cytometric dataset. Comparisons with some other available methods suggest that EMMIXuskew achieves a lower misclassification rate with respect to the labels given by benchmark gating analysis.
Musharavati, Farayi; Hamouda, Abdelmagid Salem
2015-01-01
Multiple parts process planning (MPPP) is a hard optimization problem that requires the rigor and intensity of metaheuristic-based algorithms such as simulated annealing and genetic algorithms. In this paper, a solution method for this problem is developed based on genetic algorithms. Genetic algorithms solve problems by exploring a given search space. To do this, a landscape over which the search traverses is constructed based on a number of algorithm choices. Key algorithm choices include (...
Variable length gram based file type identification algorithm%基于变长元组的文件类型识别算法
Institute of Scientific and Technical Information of China (English)
曹鼎; 罗军勇; 尹美娟
2011-01-01
快速准确地判断文件实体的真实类型对保护计算机信息安全具有重要意义.通过分析现有基于二进制内容的文件类型识别算法中存在的问题,提出采用变长元组描述文件的统计特征,并结合结构化文件中元组的分散度、稳定度以及条件广泛度设计出一种特征评估函数,从而更加准确地选取有效的特征.该算法不依靠特定文件类型的结构和关键标识,适用范围更为广泛.实验表明该算法能有效提高文件类型识别的查准率和查全率.%Fast and accurate identification of the true type of an arbitrary file is very important in information security.Concerning the problems of current content-based file type identification algorithms, variable-length gram was introduced for describing statistic characteristics of files' binary content, and a new evaluation function combining gram divergence, stability and conditional width was adopted for feature selection for structured file types. This algorithm does not rely on the structure and key words of any specific file types, which allows the approach to be applied more widely. The experimental results show that the proposed approach improves the precision and recall of file type identification.
Zanetti, Massimo; Bovolo, Francesca; Bruzzone, Lorenzo
2015-12-01
The problem of estimating the parameters of a Rayleigh-Rice mixture density is often encountered in image analysis (e.g., remote sensing and medical image processing). In this paper, we address this general problem in the framework of change detection (CD) in multitemporal and multispectral images. One widely used approach to CD in multispectral images is based on the change vector analysis. Here, the distribution of the magnitude of the difference image can be theoretically modeled by a Rayleigh-Rice mixture density. However, given the complexity of this model, in applications, a Gaussian-mixture approximation is often considered, which may affect the CD results. In this paper, we present a novel technique for parameter estimation of the Rayleigh-Rice density that is based on a specific definition of the expectation-maximization algorithm. The proposed technique, which is characterized by good theoretical properties, iteratively updates the parameters and does not depend on specific optimization routines. Several numerical experiments on synthetic data demonstrate the effectiveness of the method, which is general and can be applied to any image processing problem involving the Rayleigh-Rice mixture density. In the CD context, the Rayleigh-Rice model (which is theoretically derived) outperforms other empirical models. Experiments on real multitemporal and multispectral remote sensing images confirm the validity of the model by returning significantly higher CD accuracies than those obtained by using the state-of-the-art approaches.
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McLachlan GM
2005-01-01
Full Text Available Abstract QTL detection experiments in livestock species commonly use the half-sib design. Each male is mated to a number of females, each female producing a limited number of progeny. Analysis consists of attempting to detect associations between phenotype and genotype measured on the progeny. When family sizes are limiting experimenters may wish to incorporate as much information as possible into a single analysis. However, combining information across sires is problematic because of incomplete linkage disequilibrium between the markers and the QTL in the population. This study describes formulæ for obtaining MLEs via the expectation maximization (EM algorithm for use in a multiple-trait, multiple-family analysis. A model specifying a QTL with only two alleles, and a common within sire error variance is assumed. Compared to single-family analyses, power can be improved up to fourfold with multi-family analyses. The accuracy and precision of QTL location estimates are also substantially improved. With small family sizes, the multi-family, multi-trait analyses reduce substantially, but not totally remove, biases in QTL effect estimates. In situations where multiple QTL alleles are segregating the multi-family analysis will average out the effects of the different QTL alleles.
一种图的st编号路径长度算法%Algorithm of St-numbering Path Length of Graph
Institute of Scientific and Technical Information of China (English)
刘阳; 晏立
2013-01-01
通过对无向图的顶点标注st-编号,可以使它转换为一个有向图,根据有向图的方向可计算出从源点到汇点的路径长度.用DFS算法可计算出st-编号,但一个图有多种不同的st-编号方法,不能确定图的最长路径或者最短路径.使用移除法,连续移除根据时间戳选择出来的顶点,计算出图的st-编号,能够确定图的最长路径或者最短路径.st-编号路径长度在计算网络动态路由、计算最少着色数、减少框图高度等问题上有广泛的应用.%An undirected graph with vertices labeled St-numbering can be turned into a directed graph.The DFS algorithm can compute a st-numbering of the graph,but cannot confirm its longest or shortest path,cause a graph may have several different st-numberings.While the Removing method,which successively remove vertices selected by the timestamp,can compute the st-numbering of the graph and confirm the longest or shortest path of it.The length of st-numberings graph has a wide application in the computation of network dynamic routing and the minimum number of Graph Coloring,reduction of height of the block diagram and so on.
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César Gomes Victora
1985-02-01
Full Text Available Tentou-se acompanhar a morbi-mortalidade e o crescimento de uma coorte de 6.011 crianças urbanas nascidas em 1982 nos hospitais de Pelotas, RS, através de visitas domiciliares aos 12 meses (para uma amostra de 30% das crianças e aos 20 meses (para toda a população. Estas crianças representaram mais de 99% de todos os nascimentos urbanos naquele ano. Foi possível localizar 81% das crianças aos 12 meses e 86% aos 20 meses, devido a uma mudança na estratégia de trabalho de campo. A metodologia empregada e as principais dificuldades encontradas são descritas e as características ao nascer das crianças localizadas no acompanhamento são comparadas com as características das crianças não localizadas. A potencialidade de uso dos dados coletados é exemplificada através de alguns resultados preliminares mostrando as associações entre o peso ao nascer, a renda familiar e o estado nutricional aos 12 meses. O estudo mostra que é possível acompanhar, com uma perda relativamente pequena, uma coorte de crianças com base populacional em uma cidade brasileira de tamanho médio.A cohort of 6,011 urban children born in 1982 in the hospitals of Pelotas, Rio Grande do Sul, was followed up so that their morbidity, mortality and growth could be assessed. These children accounted for over 99% of all births in the city. A 30% sample of the children were visited at home when approximately 12 months old, and the whole population was visited at about 20 months of age. It was possible to locate 81% of the children at 12 months. This proportion increased to 86% at 24 months, due to a change in the logistics of the field work which then included visiting all 69,000 households in the city to locate children whose families had moved within the urban area. The methodology and main difficulties encountered are discussed, and the characteristics at birth of children who were located at the first follow-up visit was compared to those of children lost to
Multi-UAVs cooperative path planning based on A* fixed length search algorithm%基于A*定长搜索算法的多无人机协同航迹规划
Institute of Scientific and Technical Information of China (English)
肖自兵; 袁冬莉; 屈耀红
2012-01-01
An improved A * algorithm for fixed length path searching was proposed based on the path planning problems of multiple unmanned aerial vehicles ( UAVs) operating simultaneously. A path with fixed length was obtained by choosing nodes with costs closest to given value as best nodes in the algorithm. Then, the path was smoothed by limiting the range of the best nodes choosing from in the algorithm. Simulation results show that length error of the fixed length path obtained from the algorithm can be controlled within 1. 4% , and length error of collaborative paths is less than 0. 8%. It basically meets the requirements of multi-UAVs arriving at the same time.%基于多无人机同时作业情况下的航迹规划问题,提出了一种A*定长航迹搜索算法.该算法通过选择代价值最接近给定值的节点作为最佳节点,得到定长规划航迹,接着进一步通过限定最佳节点的选择范围,改善了航迹的可飞性.仿真结果表明,利用该算法规划的定长航迹长度误差可以控制在1.4％以内,协同航迹长度误差可以控制在0.8％以内,能够满足多无人机同时到达的一般要求.
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Maria Eloisa Salustiano
2008-10-01
Full Text Available Neste trabalho, objetivou-se verificar o efeito da temperatura na germinação e no comprimento do tubo germinativo em diferentes populações de H. vastatrix (PHVs, sob quatro temperaturas. Realizou-se um bioensaio com dez PHVs, com suspensão de urediniósporos a 0,5mg/mL em solução aquosa (0,05% de tween 80. Duas gotas de cada suspensão foram depositadas em lâminas de microscópio recobertas com camada de poliestireno e colocadas em gerbox contendo papel de filtro umedecido para constituir câmara úmida. Os gerboxes foram mantidos fechados, no escuro, a 15ºC, 20ºC, 25ºC e 30ºC, por 24 horas. O ensaio foi conduzido em fatorial 10 x 4, sendo dez isolados, quatro temperaturas e duas repetições. Avaliaram-se a germinação e o comprimento do tubo germinativo. Houve variabilidade entre as PHVs quanto à temperatura ótima para germinação e alongamento do tubo germinativo.The objective of this work was to verify the effect of temperature in germination and germ tube length in different populations of H. vastatrix (PHVs temperatures. A bioassay was performed with ten PHVs, using an urediniospore suspension of at 0.5mg/mL in aqueous solution (0.05% of tween 80. Two drops of each suspension was deposited on a microscope coverslip, covered with a polystyrene layer and incubated in gerbox containing a watered filter paper to work as a wet chamber. The gerbox was kept closed, in the dark, at 15, 20, 25 and 30ºC for 24 hours. The assay was carried out in a factorial design 10 x 4, with ten isolates, four temperatures and two replicates represented by two drops of the suspension. Germination percentage and germ tube length were assessed. There was variability among PHVs for the optimum temperature for germination and elongation of the germ tube.
Aher, Sunita B.
2014-01-01
Recommendation systems have been widely used in internet activities whose aim is to present the important and useful information to the user with little effort. Course Recommendation System is system which recommends to students the best combination of courses in engineering education system e.g. if student is interested in course like system programming then he would like to learn the course entitled compiler construction. The algorithm with combination of two data mining algorithm i.e. combination of Expectation Maximization Clustering and Apriori Association Rule Algorithm have been developed. The result of this developed algorithm is compared with Apriori Association Rule Algorithm which is an existing algorithm in open source data mining tool Weka.
Sakashita, Makiko; Kitasaka, Takayuki; Mori, Kensaku; Suenaga, Yasuhito; Nawano, Shigeru
2007-03-01
This paper presents a method for extracting multi-organs from four-phase contrasted CT images taken at different contrast timings (non-contrast, early, portal, and late phases). First, we apply a median filter to each CT image and align four-phase CT images by performing non-rigid volumetric image registration. Then, a three-dimensional joint histogram of CT values is computed from three-phase (early-, portal-, and late-) CT images. We assume that this histogram is a mixture of normal distributions corresponding to the liver, spleen, kidney, vein, artery, muscle, and bone regions. The EM algorithm is employed to estimate each normal distribution. Organ labels are assigned to each voxel using the mahalanobis distance measure. Connected component analysis is applied to correct the shape of each organ region. After that, the pancreas region is extracted from non-contrasted CT images in which other extracted organs and vessel regions are excluded. The EM algorithm is also employed for estimating the distribution of CT values inside the pancreas. We applied this method to seven cases of four-phase CT images. Extraction results show that the proposed method extracted multi-organs satisfactorily.
Arithmetic Algorithms for Hereditarily Binary Natural Numbers
Tarau, Paul
2013-01-01
We study some essential arithmetic properties of a new tree-based number representation, {\\em hereditarily binary numbers}, defined by applying recursively run-length encoding of bijective base-2 digits. Our representation expresses giant numbers like the largest known prime number and its related perfect number as well as the largest known Woodall, Cullen, Proth, Sophie Germain and twin primes as trees of small sizes. More importantly, our number representation supports novel algorithms that...
STEME: efficient EM to find motifs in large data sets
Reid, John E.; Wernisch, Lorenz
2011-01-01
MEME and many other popular motif finders use the expectation–maximization (EM) algorithm to optimize their parameters. Unfortunately, the running time of EM is linear in the length of the input sequences. This can prohibit its application to data sets of the size commonly generated by high-throughput biological techniques. A suffix tree is a data structure that can efficiently index a set of sequences. We describe an algorithm, Suffix Tree EM for Motif Elicitation (STEME), that approximates EM using suffix trees. To the best of our knowledge, this is the first application of suffix trees to EM. We provide an analysis of the expected running time of the algorithm and demonstrate that STEME runs an order of magnitude more quickly than the implementation of EM used by MEME. We give theoretical bounds for the quality of the approximation and show that, in practice, the approximation has a negligible effect on the outcome. We provide an open source implementation of the algorithm that we hope will be used to speed up existing and future motif search algorithms. PMID:21785132
Surface Length 3D: Plugin do OsiriX para cálculo da distância em superfícies
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Alexandre Campos Moraes Amato
Full Text Available Resumo Softwares tradicionais de avaliação de imagens médicas, como DICOM, possuem diversas ferramentas para mensuração de distância, área e volume. Nenhuma delas permite medir distâncias entre pontos em superfícies. O menor trajeto entre pontos possibilita o cálculo entre óstios de vasos, como no caso de aneurismas aórticos, e a avaliação dos vasos viscerais para planejamento cirúrgico. O desenvolvimento de um plugin para OsiriX para mensuração de distâncias em superfícies mostrou-se factível. A validação da ferramenta ainda se faz necessária.
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Marco Antônio Mota Gomes
2008-09-01
Full Text Available FUNDAMENTO: As diretrizes nacionais e internacionais enfatizam a importância do tratamento eficaz da hipertensão arterial. Apesar disso, verificam-se baixos índices de controle e alcance das metas preconizadas, indicando que é importante planejar e implementar melhores estratégias de tratamento. OBJETIVO: Avaliar a eficácia de um tratamento, em escalonamento de doses, tendo como base a olmesartana medoxomila. MÉTODOS: Este é um estudo aberto, nacional, multicêntrico e prospectivo, de 144 pacientes com hipertensão arterial primária nos estágios 1 e 2, virgens de tratamento ou após período de washout de duas a três semanas para aqueles em tratamento ineficaz. Avaliou-se o uso da olmesartana medoxomila num algoritmo de tratamento, em quatro fases: (i monoterapia (20 mg, (ii-iii associada à hidroclorotiazida (20/12,5 mg e 40/25 mg e (iv adição de besilato de anlodipino (40/25 mg + 5 mg. RESULTADOS: Ao fim do tratamento, em escalonamento, 86% dos sujeitos de pesquisa alcançaram a meta de pressão arterial (PA 20 mmHg foi de 87,5% e diastólicos (PAD > 10 mmHg de 92,4%. CONCLUSÃO: O estudo se baseou em um esquema de tratamento semelhante à abordagem terapêutica da prática clínica diária e mostrou que o uso da olmesartana medoxomila, em monoterapia ou em associação a hidroclorotiazida e anlodipino, foi eficaz para o alcance de meta para hipertensos dos estágios 1 e 2.BACKGROUND: The national and international guidelines emphasize the importance of the effective treatment of essenssial hypertension. Nevertheless, low levels of control are observed, as well as low attainment of the recommended goals, indicating that it is important to plan and implement better treatment strategies. OBJECTIVE: To evaluate the efficacy of a based treatment algorithm with olmesartan medoxomil. METHODS: This is an open, national, multicentric and prospective study of 144 patients with primary arterial hypertension, stages 1 and 2, naïve to
Institute of Scientific and Technical Information of China (English)
廖福蓉; 王成良
2012-01-01
频繁项集的挖掘受到大量候选频繁项集和较高计算花费的限制,只挖掘最大长度频繁项集已满足很多应用.提出一种基于有序FP-tree结构挖掘最大长度频繁项集的算法.即对有序FP-tree的头表进行改造,增加一个max-level域,记录该项在有序FP-tree中的最大高度.挖掘时仅对max-level大于等于已有最大长度频繁项集长度的项进行遍历,不产生条件模式基,无需递归构造条件FP-tree,且计算出最大长度频繁项集的支持度.实验结果表明该算法挖掘效率高、速度快.%The mining of frequent itemsets has been limited by the large number of resulting itemsets as well as the high computational cost. In many application domains, however, it is often sufficient to mine maximum length frequent itemsets. An order FP-tree-based algorithm is proposed for the mining problem. A field max-level is added in head-table to record the greatest height of item. In the mining process, only the item which max-level value is equal or greater than the length of existing maximum length frequent itemsets is traversed. Neither producing conditional pattern base nor constructing conditional frequent pattern tree recursively is needed, and the support of maximum length frequent itemsets is calculated. The experimental results show that the algorithm accelerates the speed to traverse the tree and improves the mining efficiency.
Institute of Scientific and Technical Information of China (English)
王继霞; 刘次华
2011-01-01
研究含有缺失数据的多元正态模型参数的极大似然估计问题,利用Monte Carlo EM算法求得多元正态模型参数的迭代解,并证明了此迭代解收敛到最优解,且其收敛速度是二阶的.%Maximum likelihood estimations of the parameters of multivariate normal distribution models under missing data were studied. The iterative solution of the parameters of multivariate normal distribution models were obtained through the Monte Carlo EM algorithm and this solution converge to the optimum solution were proved and the convergence rate of this solution was secondary.
Goerg, Georg M
2011-01-01
In this work I propose a frequency domain adaptation of the Expectation Maximization (EM) algorithm to separate a family of sequential observations in classes of similar dynamic structure, which can either mean non-stationary signals of similar shape, or stationary signals with similar auto-covariance function. It does this by viewing the magnitude of the discrete Fourier transform (DFT) of the signals (or power spectrum) as a probability density/mass function (pdf/pmf) on the unit circle: signals with similar dynamics have similar pdfs; distinct patterns have distinct pdfs. An advantage of this approach is that it does not rely on any parametric form of the dynamic structure, but can be used for non-parametric, robust and model-free classi?cation. Applications to neural spike sorting (non-stationary) and pattern-recognition in socio-economic time series (stationary) demonstrate the usefulness and wide applicability of the proposed method.
Earth Data Analysis Center, University of New Mexico — Flame length was modeled using FlamMap, an interagency fire behavior mapping and analysis program that computes potential fire behavior characteristics. The tool...
Biswas, Abhishek; Ranjan, Desh; Zubair, Mohammad; He, Jing
2015-09-01
The determination of secondary structure topology is a critical step in deriving the atomic structures from the protein density maps obtained from electron cryomicroscopy technique. This step often relies on matching the secondary structure traces detected from the protein density map to the secondary structure sequence segments predicted from the amino acid sequence. Due to inaccuracies in both sources of information, a pool of possible secondary structure positions needs to be sampled. One way to approach the problem is to first derive a small number of possible topologies using existing matching algorithms, and then find the optimal placement for each possible topology. We present a dynamic programming method of Θ(Nq(2)h) to find the optimal placement for a secondary structure topology. We show that our algorithm requires significantly less computational time than the brute force method that is in the order of Θ(q(N) h).
Al-Jabr, Ahmad Ali
2013-01-01
This paper presents methods of simulating gain media in the finite difference time-domain (FDTD) algorithm utilizing a generalized polarization formulation. The gain can be static or dynamic. For static gain, Lorentzian and non-Lorentzian models are presented and tested. For the dynamic gain, rate equations for two-level and four-level models are incorporated in the FDTD scheme. The simulation results conform with the expected behavior of wave amplification and dynamic population inversion.
Abed, Azher M.; Abed, Issa Ahmed; Majdi, Hasan Sh.; Al-Shamani, Ali Najah; Sopian, K.
2016-12-01
This study proposes a new procedure for optimal design of shell and tube heat exchangers. The electromagnetism-like algorithm is applied to save on heat exchanger capital cost and designing a compact, high performance heat exchanger with effective use of the allowable pressure drop (cost of the pump). An optimization algorithm is then utilized to determine the optimal values of both geometric design parameters and maximum allowable pressure drop by pursuing the minimization of a total cost function. A computer code is developed for the optimal shell and tube heat exchangers. Different test cases are solved to demonstrate the effectiveness and ability of the proposed algorithm. Results are also compared with those obtained by other approaches available in the literature. The comparisons indicate that a proposed design procedure can be successfully applied in the optimal design of shell and tube heat exchangers. In particular, in the examined cases a reduction of total costs up to 30, 29, and 56.15 % compared with the original design and up to 18, 5.5 and 7.4 % compared with other approaches for case study 1, 2 and 3 respectively, are observed. In this work, economic optimization resulting from the proposed design procedure are relevant especially when the size/volume is critical for high performance and compact unit, moderate volume and cost are needed.
Length and coverage of inhibitory decision rules
Alsolami, Fawaz
2012-01-01
Authors present algorithms for optimization of inhibitory rules relative to the length and coverage. Inhibitory rules have a relation "attribute ≠ value" on the right-hand side. The considered algorithms are based on extensions of dynamic programming. Paper contains also comparison of length and coverage of inhibitory rules constructed by a greedy algorithm and by the dynamic programming algorithm. © 2012 Springer-Verlag.
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Rodrigo Bomeny de Paulo
2009-01-01
Full Text Available OBJETIVOS: Os objetivos deste trabalho foram: avaliar as complicações e o tempo de internação de doentes com acidente vascular cerebral isquêmico (AVCI na fase aguda ou subaguda em uma enfermaria de Neurologia geral em São Paulo; investigar a influência de idade, fatores de risco para doença vascular, território arterial acometido e etiologia sobre as complicações e o tempo de internação. MÉTODOS: Foram coletados prospectivamente dados de 191 doentes com AVCI e posteriormente analisados. RESULTADOS: Cinquenta e um doentes (26,7% apresentaram alguma complicação clínica durante a internação. A pneumonia foi a complicação mais frequente. O tempo médio de internação na enfermaria foi de 16,8±13,8 dias. Na análise multivariável, o único fator que se correlacionou significativamente com menor taxa de complicações foi idade mais jovem (OR=0,92-0,97, p INTRODUCTION: Purposes of this study were: evaluate complications and length of stay of patients admitted with diagnosis of ischemic stroke (IS in the acute or subacute phase, in a general Neurology ward in São paulo, Brazil; investigate the influence of age, risk factors for vascular disease, arterial territory and etiology. METHODS: Data from 191 IS patients were collected prospectively. RESULTS: Fifty-one patients (26.7% presented at least one clinical complication during stay. pneumonia was the most frequent complication. Mean length of stay was 16.8+-13.8 days. Multivariate analysis revealed a correlation between younger age and lower complication rates (OR=0.92-0.97, p < 0.001. presence of complications was the only factor that independently influenced length of stay (OR=4.20; CI=1.928.84; p<0.0001. CONCLUSION: These results should be considered in the planning and organization of IS care in Brazil.
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Paulo Afonso Nunes Nassif
2009-09-01
Full Text Available RACIONAL: Segundo a hipótese do intestino longo, o comprimento do intestino delgado estaria relacionado à obesidade. Existem dados evolutivos, anatômicos e neuroendócrinos em favor desta afirmação. OBJETIVOS: Verificar a medida do comprimento do intestino delgado em pacientes obesos submetidos à cirurgia bariátrica e analisar a correlação entre o seu tamanho e o IMC. MÉTODO: A casuística foi composta de 30 pacientes do Serviço de Obesidade do Hospital Universitário Evangélico de Curitiba, submetidos à cirurgia bariátrica no período de março a junho de 2009, e previamente avaliados, verificando peso, altura e IMC. A técnica cirúrgica foi a de Fobi-Capella. A mensuração do intestino delgado foi realizada desde a flexura duodenojejunal à junção ileocecal, durante o trans-operatório, utilizando uma pinça de manipulação intestinal, a qual foi marcada com a medida de 10 cm. As alças intestinais foram medidas na margem anti-mesentérica, aplicando-se tensão mínima necessária para retificar as mesmas. Os dados foram correlacionados e tabulados estatisticamente, utilizando-se o método de correlação de Pearson. RESULTADOS: A média do comprimento intestinal para o sexo masculino foi de 582,5 cm e para o sexo feminino de 509,1. A partir do cálculo do coeficiente de correlação de Pearson, confirmou-se a ausência de correlação entre IMC e comprimento do intestino delgado. CONCLUSÃO: Obteve-se uma média de tamanho intestinal de 528,7 cm para toda a amostra. O comprimento do intestino delgado não possuiu correspondência com o IMC, não sendo um fator de significância neste estudo.BACKGROUND: According to the hypothesis of long bowel, the length of small intestine is related to obesity. There are evolutionary, anatomics, neuroendocrines evidences in favor of this assertion. AIM: To check the measure of the small intestine length in overweight patients submitted to bariatric surgery and to analyze the correlation
2PL模型的EM缺失数据处理方法研究%Extension of EM Algorithm for Finite Mixture in IRT for Missing Response Data
Institute of Scientific and Technical Information of China (English)
张淑梅; 辛涛; 曾莉; 孙佳楠
2011-01-01
Item Response Theory (IRT) model is a dramatically important model in educational and psychological measurement. There are two kinds of parameters in the model - item parameters and ability parameters. Nowadays, a commonly used method for estimating item parameters of IRT model is given by Woodruff and Hanson (1997). They treated the ability parameter θ as missing and applied EM Algorithm for finite mixture to estimate item parameters under the condition that the examinees' responses are complete. Here, we extend the Woodruff's method to deal with incomplete response data. That is,we keep the incomplete response cases and regard missing response data as "missing" like θ and then apply EM Algorithm. In our simulation study, we compare the relative performance of the missing data treatment method of us with that of the software BILOG-MG under different sample size and missing ratio. The simulation results show that our new method can obtain better estimation than BILOG-MG in most cases.%项目反应理论(IRT)模型是教育统计与测量中一种十分重要的模型,它包含项目参数和能力参数.目前一种常用的估计IRT模型项目参数的方法是由Woodruff和Hanson(1997)应用EM算法给出的,它用于完全反应数据,而把能力参数看作缺失数据.本文将Woodruff的方法推广到处理缺失反应的情况,基本思想是把能力参数和缺失反应均看作缺失数据,再运用EM算法估计参数.通过模拟研究,在不同被试人数和不同缺失比例的情况下,本文比较了我们给出的方法和BILOG-MG软件的缺失数据处理方法的参数估计效果.结果表明,在大多数情况下,本文提出的方法能得到更好的估计.
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Feng Xu
2012-05-01
Full Text Available Heat shock proteins (HSPs play various stress-protective roles in plants. In this study, three <em>HSP> genes were isolated from a suppression subtractive hybridization (SSH cDNA library of <em>Ginkgo bilobaem> leaves treated with cold stress. Based on the molecular weight, the three genes were designated <em>GbHSP16.8em>, <em>GbHSP17em> and <em>GbHSP70em>. The full length of the three genes were predicted to encode three polypeptide chains containing 149 amino acids (Aa, 152 Aa, and 657 Aa, and their corresponding molecular weights were predicted as follows: 16.67 kDa, 17.39 kDa, and 71.81 kDa respectively. The three genes exhibited distinctive expression patterns in different organs or development stages. <em>GbHSP16.8em> and <em>GbHSP70em> showed high expression levels in leaves and a low level in gynoecia, <em>GbHSP17em> showed a higher transcription in stamens and lower level in fruit. This result indicates that <em>GbHSP16.8em> and <em>GbHSP70 em>may play important roles in <em>Ginkgo> leaf development and photosynthesis, and <em>GbHSP17em> may play a positive role in pollen maturation. All three <em>GbHSPs> were up-regulated under cold stress, whereas extreme heat stress only caused up-regulation of <em>GbHSP70em>, UV-B treatment resulted in up-regulation of <em>GbHSP16.8em> and <em>GbHSP17em>, wounding treatment resulted in up-regulation of <em>GbHSP16.8em> and <em>GbHSP70em>, and abscisic acid (ABA treatment caused up-regulation of <em>GbHSP70em> primarily.
Directory of Open Access Journals (Sweden)
Ana Beatriz Francioso de Oliveira
2010-09-01
Full Text Available OBJETIVO: A unidade de terapia intensiva é sinônimo de gravidade e apresenta taxa de mortalidade entre 5,4% e 33%. Com o aperfeiçoamento de novas tecnologias, o paciente pode ser mantido por longo período nessa unidade, ocasionando altos custos financeiros, morais e psicológicos para todos os envolvidos. O objetivo do presente estudo foi avaliar os fatores associados à maior mortalidade e tempo de internação prolongado em uma unidade de terapia intensiva adulto. MÉTODOS: Participaram deste estudo todos os pacientes admitidos consecutivamente na unidade de terapia intensiva de adultos, clínica/cirúrgica do Hospital das Clínicas da Universidade Estadual de Campinas, no período de seis meses. Foram coletados dados como: sexo, idade, diagnóstico, antecedentes pessoais, APACHE II, dias de ventilação mecânica invasiva, reintubação orotraqueal, traqueostomia, dias de internação na unidade de terapia intensiva, alta ou óbito na unidade de terapia intensiva. RESULTADOS: Foram incluídos no estudo 401 pacientes, sendo 59,6% homens e 40,4% mulheres, com idade média de 53,8±18,0 anos. A média de internação na unidade de terapia intensiva foi de 8,2±10,8 dias, com taxa de mortalidade de 13,46%. Dados significativos para mortalidade e tempo de internação prolongado em unidade de terapia intensiva (p11, traqueostomia e reintubação. CONCLUSÃO: APACHE >11, traqueostomia e reintubação estiveram associados, neste estudo, à maior taxa de mortalidade e tempo de permanência prolongado em unidade de terapia intensiva.OBJECTIVE: The intensive care unit is synonymous of high severity, and its mortality rates are between 5.4 and 33%. With the development of new technologies, a patient can be maintained for long time in the unit, causing high costs, psychological and moral for all involved. This study aimed to evaluate the risk factors for mortality and prolonged length of stay in an adult intensive care unit. METHODS: The study
Institute of Scientific and Technical Information of China (English)
孙聚波; 徐平峰
2015-01-01
图模型是处理高维数据的有力工具,其中图模型的选择是统计推断的重要方面.利用E-MS算法进行缺失数据的图模型选择.E-MS算法是基于EM迭代思想的,把模型下的参数和模型选择参数统一为新的参数,这样模型选择就成为E-M迭代过程的一部分.最后给出了3,4,5变量情形下的模拟研究.%Graphical model is a powerful tool to deal with high dimensional data, and the graphical model selection is an important aspect of statistical inference.In this paper, the E-MS algorithm was used to select the appropriate graphical model with missing data.The E-MS algorithm is based on the idea of EM iteration, and combines the parameters of the model with the model selection parameters as the new parameters, so the model selection becomes the part of the E-M iterative process.Finally, a simulation study of 3, 4 and 5 variables was given.
Baer, Michael B
2008-01-01
Huffman coding finds an optimal prefix code for a given probability mass function. Consider situations in which one wishes to find an optimal code with the restriction that all codewords have lengths that lie in a user-specified set of lengths (or, equivalently, no codewords have lengths that lie in a complementary set). This paper introduces a polynomial-time dynamic programming algorithm that finds optimal codes for this reserved-length prefix coding problem. This has applications to quickly encoding and decoding lossless codes. In addition, one modification of the approach solves any quasiarithmetic prefix coding problem, while another finds optimal codes restricted to the set of codes with g codeword lengths for user-specified g (e.g., g=2).
National Research Council Canada - National Science Library
Marco Antônio Mota Gomes; Audes Diógenes de Magalhães Feitosa; Wille Oigman; José Márcio Ribeiro; Emílio Hideyuki Moriguchi; José Francisco Kerr Saraiva; Dalton Bertolim Précoma; Artur Beltrame Ribeiro; Celso Amodeo; Andréa Araujo Brandão
2008-01-01
... após período de washout de duas a três semanas para aqueles em tratamento ineficaz. Avaliou-se o uso da olmesartana medoxomila num algoritmo de tratamento, em quatro fases: (i) monoterapia (20 mg), (ii-iii) associada à hidroclorotiazida...
Institute of Scientific and Technical Information of China (English)
赵越; 李红
2016-01-01
针对标准EM算法在汉语分词的应用中还存在收敛性能不好、分词准确性不高的问题，本文提出了一种基于极大似然估计规则优化EM算法的汉语分词认知模型，首先使用当前词的概率值计算每个可能切分的可能性，对切分可能性进行“归一化”处理，并对每种切分进行词计数，然后针对标准EM算法得到的估计值只能保证收敛到似然函数的一个稳定点，并不能使其保证收敛到全局最大值点或者局部最大值点的问题，采用极大似然估计规则对其进行优化，从而可以使用非线性最优化中的有效方法进行求解达到加速收敛的目的。仿真试验结果表明，本文提出的基于极大似然估计规则优化EM算法的汉语分词认知模型收敛性能更好，且在汉语分词的精确性较高。%In view of bad convergence and inaccurate word segmentation of standard EM algorithm in Chinese words segmentation, this paper put forward a cognitive model based on optimized EM algorithm by maximum likelihood estimation rule. Firstly, it uses the probability of current word to calculate the possibility of each possible segmentation and normalize them. Each segmentation is counted by words. Standard EM algorithm cannot make sure converging to a stable point of likelihood function, and converging to a global or local maximum point. Therefore, the maximum likelihood estimation rule is adopted to optimize it so as to use an effective method in nonlinear optimization and accelerate the convergence. the simulation experiments show that the optimized EM algorithm by maximum likelihood estimation rule has better convergence performance in the Chinese words cognitive model and more accurate in the words segmentation.
National Research Council Canada - National Science Library
Marco Antônio Mota Gomes; Audes Diógenes de Magalhães Feitosa; Wille Oigman; José Márcio Ribeiro; Emílio Hideyuki Moriguchi; José Francisco Kerr Saraiva; Dalton Bertolim Précoma; Artur Beltrame Ribeiro; Celso Amodeo; Andréa Araujo Brandão
2008-01-01
... importante planejar e implementar melhores estratégias de tratamento. OBJETIVO: Avaliar a eficácia de um tratamento, em escalonamento de doses, tendo como base a olmesartana medoxomila. MÉTODOS: Este é...
Directory of Open Access Journals (Sweden)
Ana Paula Iannoni
2006-04-01
Full Text Available O modelo hipercubo, conhecido na literatura de problemas de localização de sistemas servidor para cliente, é um modelo baseado em teoria de filas espacialmente distribuídas e aproximações Markovianas. O modelo pode ser modificado para analisar os sistemas de atendimentos emergenciais (SAEs em rodovias, considerando as particularidades da política de despacho destes sistemas. Neste estudo, combinou-se o modelo hipercubo com um algoritmo genético para otimizar a configuração e operação de SAEs em rodovias. A abordagem é efetiva para apoiar decisões relacionadas ao planejamento e operação destes sistemas, por exemplo, em determinar o tamanho ideal para as áreas de cobertura de cada ambulância, de forma a minimizar o tempo médio de resposta aos usuários e o desbalanceamento das cargas de trabalho das ambulâncias. Os resultados computacionais desta abordagem foram analisados utilizando dados reais do sistema Anjos do Asfalto (rodovia Presidente Dutra.The hypercube model, well-known in the literature on problems of server-to-customer localization systems, is based on the spatially distributed queuing theory and Markovian analysis approximations. The model can be modified to analyze Emergency Medical Systems (EMSs on highways, considering the particularities of these systems' dispatching policies. In this study, we combine the hypercube model with a genetic algorithm to optimize the configuration and operation of EMSs on highways. This approach is effective to support planning and operation decisions, such as determining the ideal size of the area each ambulance should cover to minimize not only the average time of response to the user but also ambulance workload imbalances, as well as generating a Pareto efficient boundary between these measures. The computational results of this approach were analyzed using real data Anjos do Asfalto EMS (which covers the Presidente Dutra highway.
Directory of Open Access Journals (Sweden)
Maria da Cruz CL Moura
2010-06-01
Full Text Available A estimativa da variabilidade genética existente em um banco de germoplasma é importante não só para a conservação dos recursos genéticos, mas também para sua utilização no melhoramento de plantas. Os acessos de um banco são estudados com base em descritores quantitativos e qualitativos. Porém, nem sempre esses dados são analisados simultaneamente. O presente trabalho teve como objetivo estudar a divergência genética entre 56 acessos de Capsicum chinense procedentes da Coleção de Germoplasma da Universidade Estadual do Norte Fluminense Darcy Ribeiro, com base em 44 descritores morfoagronômicos, 37 qualitativos e sete quantitativos, utilizando-se a análise conjunta baseada no algoritmo de Gower. Utilizou-se o delineamento inteiramente ao acaso, com três repetições e três plantas por parcela. As plantas estudadas cresceram em vasos de 5 L. Houve variabilidade fenotípica entre os acessos de pimenta estudados, principalmente nos frutos, que mostraram diferenças acentuadas em tamanho, formato, coloração, teores de sólidos solúveis totais e vitamina C. O método aglomerativo utilizado foi UPGMA por ter maior coeficiente de correlação cofenética (r = 0,82. Os acessos estudados dividiram-se em seis grupos. O agrupamento com base na distância de Gower revelou maior eficiência na disjunção dos genótipos quando foram utilizadas as variáveis qualitativas em comparação às quantitativas, indicando uma maior contribuição daquelas na explicação dos agrupamentos. A análise conjunta dos dados quantitativos e qualitativos resultou em maior eficiência na determinação da divergência genética entre os acessos avaliados, sendo uma alternativa viável e uma ferramenta importante para o conhecimento da variabilidade em bancos de germoplasma.The estimation of genetic variability in germplasm collections is important not only for the conservation of genetic resources, but also for plant breeding purposes. Accessions in a
Parallel Expectation-Maximization Algorithm for Large Databases
Institute of Scientific and Technical Information of China (English)
HUANG Hao; SONG Han-tao; LU Yu-chang
2006-01-01
A new parallel expectation-maximization (EM) algorithm is proposed for large databases. The purpose of the algorithm is to accelerate the operation of the EM algorithm. As a well-known algorithm for estimation in generic statistical problems, the EM algorithm has been widely used in many domains. But it often requires significant computational resources. So it is needed to develop more elaborate methods to adapt the databases to a large number of records or large dimensionality. The parallel EM algorithm is based on partial E-steps which has the standard convergence guarantee of EM. The algorithm utilizes fully the advantage of parallel computation. It was confirmed that the algorithm obtains about 2.6 speedups in contrast with the standard EM algorithm through its application to large databases. The running time will decrease near linearly when the number of processors increasing.
Directory of Open Access Journals (Sweden)
Tomasz SEKUTOWSKI
2015-09-01
Full Text Available Seed germination and early growth microbiotest PhytotoxkitTM was used in the experiment, which consisted of 3 independent laboratory experimental series with one month intervals each and 3 replications. The aim of this study was to evaluate germination dynamics and capacity as well as selected biometric parameters after seed treatment with two preparations containing effective microorganisms: EM Farma (EMF and EM Farma Plus (EMFP. Sunflower seeds (H. annuus were chosen as the experimental material. Seeds soaked in distilled water were control objects (K in these experiment. Apart from control (K, reference material was prepared in the form of two biostimulants: Kelpak SL (KSL and gibberellic acid (GA3. The effect of the two biopreparations EM Farma (EMF and EM Farma Plus (EMFP was beneficial related to germination capacity and biometric parameters of sunflower (H. annuus.
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The genome length is a fundamental feature of a species. This note outlined the general concept and estimation method of the physical and genetic length. Some formulae for estimating the genetic length were derived in detail. As examples, the genome genetic length of Pinus pinaster Ait. and the genetic length of chromosome Ⅵ of Oryza sativa L. were estimated from partial linkage data.
Directory of Open Access Journals (Sweden)
J.C.M.C. Rocha
2005-12-01
Full Text Available Variance components were estimated for gestation length fitting the additive direct effect of calf, maternal genetic effect and sire effect as random effects. The statistical models also included the fixed effects of contemporary group, that included the date of breeding (AI, date of birth, and sex of calf, and the covariate age of dam at calving (linear and quadratic. Two different models were used, model 1 considering GL as a trait of the calf, and model 2 considering GL as a trait of the dam. The means of gestation length for the purebred animals were 294.55 days (males and 293.34 days (females, while for the crossbred animals they were 292.49 days (males and 292.55 days (females. Variance components for the purebred animals, fitting model 1, were 14.47, 72.78 and 57.31, for the additive genetic (sigma2a, total phenotypic (sigma2p and residual (sigma2e effects, respectively, with a heritability estimate of 0.21. For the crossbred animals, variance components for sigma2a, sigma2p, sigma2e were 90.40, 127.35 and 36.95, respectively, with a heritability of 0.71. Fitting model 2, the estimated variance components for the purebred animals were 12.78, 5.01, 74.84 and 57.05 for sigma2a , sire of calf (sigma ²asire, sigma2p, and sigma2e , respectively. The sire effect accounted for 0.07 (c² of the phenotypic variance and the coefficient of repeatability was 0.17. For the crossbred animals, the variance components were 22.11 (sigma2a , 22.97 (sigma ²asire , 127.70 (sigma2p and 82.61 (sigma2e, while c² was 0.18 and repeatability was 0.17. Therefore, regarding selection of beef cattle, it is suggested to use the heritability estimate obtained by model 1, where GL is considered as a trait of the calf.Estimaram-se os componentes de variância do período de gestação (PG considerando-se o efeito direto do bezerro e os efeitos direto da vaca e aleatório do touro (pai do bezerro. Além dos efeitos aleatórios, os modelos estatísticos incluíram os
基于期望值最大算法和离散小波框架的图像融合%Image Fusion Based on EM Algorithm and Discrete Wavelete Frame
Institute of Scientific and Technical Information of China (English)
刘刚; 敬忠良; 孙韶媛
2005-01-01
The discrete wavelet transform has become an attractive tool for fusing multisensor images. This paper investigates the discrete wavelet frame transform. A major advantage of this method over discrete wavelet transform is aliasing free and translation invariant. The discrete wavelet frame (DWF) transform is used to decompose the registered images into multiscale representation with the low frequency and the high frequency bands. The low frequency band is normalized and fused by using the expectation maximization (EM) algorithm. The informative importance measure is applied to the high frequency band. The final fused image is obtained by taking the inverse transform on the composite coefficient representations. Experiments show that the proposed method is more effective than conventional image fusion methods.
Marco Antônio Mota Gomes; Audes Diógenes de Magalhães Feitosa; Wille Oigman; José Márcio Ribeiro; Emílio Hideyuki Moriguchi; José Francisco Kerr Saraiva; Dalton Bertolim Précoma; Artur Beltrame Ribeiro; Celso Amodeo; Andréa Araujo Brandão
2008-01-01
FUNDAMENTO: As diretrizes nacionais e internacionais enfatizam a importância do tratamento eficaz da hipertensão arterial. Apesar disso, verificam-se baixos índices de controle e alcance das metas preconizadas, indicando que é importante planejar e implementar melhores estratégias de tratamento. OBJETIVO: Avaliar a eficácia de um tratamento, em escalonamento de doses, tendo como base a olmesartana medoxomila. MÉTODOS: Este é um estudo aberto, nacional, multicêntrico e prospectivo, de 144 paci...
Energy Technology Data Exchange (ETDEWEB)
Souza, Claudio Eduardo Scriptori de
1996-02-01
In the Operating Center of Electrical Energy System has been every time more and more important the understanding of the difficulties related to the electrical power behavior. In order to have adequate operation of the system the state estimation process is very important. However before performing the system state estimation owe needs to know if the system is observable otherwise the estimation will no be possible. This work has a main objective, to develop a software that allows one to visualize the whole network in case that network is observable or the observable island of the entire network. As theoretical background the theories and algorithm using the triangular factorization of gain matrix as well as the concepts contained on factorization path developed by Bretas et alli were used. The algorithm developed by him was adapted to the Windows graphical form so that the numerical results of the network observability are shown in the computer screen in graphical form. This algorithm is essentially instead of numerical as the one based on the factorization of gain matrix only. To implement the algorithm previously referred it was used the Borland C++ compiler for windows version 4.0 due to the facilities for sources generation it presents. The results of the tests in the network with 6, 14 and 30 bus leads to: (1) the simplification of observability analysis, using sparse vectors and triangular factorization of the gain matrix; (2) the behavior similarity of the three testes systems with effective clues that the routine developed works well for any systems mainly for systems with bigger quantities of bus and lines; (3) the alternative way of presenting numerical results using the program developed here in graphical forms. (author)
Institute of Scientific and Technical Information of China (English)
王继霞; 刘次华
2009-01-01
In this paper,a geometric response and normal covariace model for the missing data are assumed.We fit the model using the Monte Carlo EM(Expectation and Maximization) algorithm.The E-step is derived by Metropolis-Hastings algorithm to generate a sample for missing data,and the M-Step is done by Newton-Raphson to maximize the likelihood function.Asymptotic variances and the standard errors of the MLE of parameters are derived using the observed Fisher information.%本文研究缺失数据下对数线性模型参数的极大似然估计问题.通过Monte-Carlo EM算法去拟合所提出的模型.其中,在期望步中利用Metropolis-Hastings算法产生一个缺失数据的样本,在最大化步中利用Newton-Raphson迭代使似然函数最大化.最后,利用观测数据的Fisher信息得到参数极大似然估计的渐近方差和标准误差.
Directory of Open Access Journals (Sweden)
Jucelma de Cássia C. Tolotti Mainardi
2004-12-01
Full Text Available O objetivo do trabalho foi avaliar a resposta quanto ao ciclo e comprimento, largura e área da folha, ao redutor de crescimento Daminozide, pulverizado na cultivar de crisântemo (Dendranthema grandiflora Tzvelev. de corte Snowdon, conduzida em vaso. O estudo foi composto por dois ensaios com cinco repetições, no delineamento experimental inteiramente casualizado bifatorial 4 x 2, sendo formado por quatro doses de Daminozide (0, 2000, 4000 e 6000 mg.L-1 e duas freqüências de aplicações (semanal e bissemanal. Os resultados mostraram que a cultivar Snowdon pode ser conduzida em vaso, porém, com aumento de ciclo e redução de até 28% na área da folha.The aim of this study was to investigate the response of cultivation cycle, length, width and area leaf, to the growth retardant Daminozide, sprayed on the Chrysanthemum (Dendranthema grandiflora Tzvelev. ‘Snowdon’ cultivated in pot. The study consisted of two experiments with five repetitions. The experiments were bifactorial 4 x 2, with four concentrations of Daminozide (0, 2.000, 4.000 and 6.000 mg.L-1 and two frequencies of application (weekly and bi-weekly of product. Cultivation cycle, leaf length, width and area were determined. The ‘Snowdon’ was able to produce pots commercially acceptable, with increase in the cultivation cycle and decrease of the leaf size.
Energy Technology Data Exchange (ETDEWEB)
Siqueira, Newton Norat
2006-12-15
This work shows a new approach to solve availability maximization problems in electromechanical systems, under periodic preventive scheduled tests. This approach uses a new Optimization tool called PSO developed by Kennedy and Eberhart (2001), Particle Swarm Optimization, integrated with probabilistic safety analysis model. Two maintenance optimization problems are solved by the proposed technique, the first one is a hypothetical electromechanical configuration and the second one is a real case from a nuclear power plant (Emergency Diesel Generators). For both problem PSO is compared to a genetic algorithm (GA). In the experiments made, PSO was able to obtain results comparable or even slightly better than those obtained b GA. Therefore, the PSO algorithm is simpler and its convergence is faster, indicating that PSO is a good alternative for solving such kind of problems. (author)
Length-Dependent Electromigration Behavior of Sn58Bi Solder and Critical Length of Electromigration
Zhao, Xu; Muraoka, Mikio; Saka, Masumi
2017-02-01
On the basis of a developed test structure, electromigration (EM) tests of Sn58Bi solder strips with lengths of 50 μm, 100 μm, and 150 μm were simultaneously conducted at a current density of 27 kA/cm2 at 373 K. Length-dependent EM behavior was detected, and the mechanism is discussed. Bi atoms were segregated to the anode side more easily as the strip length increased, which resulted in the formation of a thicker Bi-rich layer or Sn-Bi mixed hillocks. The results reveal the existence of back flow that depends on the solder joint length. The back flow is most likely caused by an oxide layer formed on the Sn58Bi solder. By measuring the thicknesses of the Bi-rich layers, the Bi drift velocities were obtained. The critical length of the solder joint and the critical product of the length and the current density were estimated to be 16 μm and 43 A/cm, respectively. This observation will assist design of advanced electronic devices to anticipate EM reliability.
Directory of Open Access Journals (Sweden)
Xuemei Liu
2012-09-01
Full Text Available Cellulose synthase (CESA, which is an essential catalyst for the generation of plant cell wall biomass, is mainly encoded by the <em>CesA> gene family that contains ten or more members. In this study; four full-length cDNAs encoding CESA were isolated from<em> Betula platyphyllaem> Suk., which is an important timber species, using RT-PCR combined with the RACE method and were named as <em>BplCesA3em>, <em>−4em>,> −7 em>and> −8em>. These deduced CESAs contained the same typical domains and regions as their <em>Arabidopsis> homologs. The cDNA lengths differed among these four genes, as did the locations of the various protein domains inferred from the deduced amino acid sequences, which shared amino acid sequence identities ranging from only 63.8% to 70.5%. Real-time RT-PCR showed that all four <em>BplCesAs> were expressed at different levels in diverse tissues. Results indicated that BplCESA8 might be involved in secondary cell wall biosynthesis and floral development. BplCESA3 appeared in a unique expression pattern and was possibly involved in primary cell wall biosynthesis and seed development; it might also be related to the homogalacturonan synthesis. BplCESA7 and BplCESA4 may be related to the formation of a cellulose synthase complex and participate mainly in secondary cell wall biosynthesis. The extremely low expression abundance of the four BplCESAs in mature pollen suggested very little involvement of them in mature pollen formation in <em>Betula>. The distinct expression pattern of the four <em>BplCesAs> suggested they might participate in developments of various tissues and that they are possibly controlled by distinct mechanisms in <em>Betula.>
Institute of Scientific and Technical Information of China (English)
张智晟; 龚文杰; 于强; 常德政
2012-01-01
提出基于类电磁机制算法的对角递归神经网络的风电功率预测模型.对角递归神经网络属于动态递归神经网络,具有较好的动态性能；类电磁机制算法模拟电磁场中带电粒子间吸引与排斥机制,可进行全局优化,具有好的收敛性能.模型采用类电磁机制算法对对角递归神经网络进行优化,可避免使神经网络训练陷入局部最小点,提高模型的预测精度.仿真结果表明,模型可有效降低预测误差,获得满意的预测精度.%Diagonal recursive neural network based wind power forecasting model using electro-magnetism-like mechanism algorithm is constructed in this paper. The diagonal recursive neural network is contained in dynamic recursive neural network, which possesses good dynamic performance. Electromagnetism-like mechanism algorithm simulates attraction and repulsion mechanism for particles in the electromagnetic field. It possesses global optimization ability and good convergence performance. Diagonal recursive neural network is optimized by electromagnetism-like mechanism algorithm, which can avoid neural network to immerse in the local minimal points and improve the forecasting precision. The testing results show that the proposed forecasting mode can reduce forecasting error and obtain satisfactory forecasting precision.
Measuring Thermodynamic Length
Energy Technology Data Exchange (ETDEWEB)
Crooks, Gavin E
2007-09-07
Thermodynamic length is a metric distance between equilibrium thermodynamic states. Among other interesting properties, this metric asymptotically bounds the dissipation induced by a finite time transformation of a thermodynamic system. It is also connected to the Jensen-Shannon divergence, Fisher information, and Rao's entropy differential metric. Therefore, thermodynamic length is of central interestin understanding matter out of equilibrium. In this Letter, we will consider how to denethermodynamic length for a small system described by equilibrium statistical mechanics and how to measure thermodynamic length within a computer simulation. Surprisingly, Bennett's classic acceptance ratio method for measuring free energy differences also measures thermodynamic length.
Directory of Open Access Journals (Sweden)
Leandro Muller Gomiero
2008-04-01
Full Text Available Analisou-se a relação peso-comprimento e o fator de condição de Cichla kelberi introduzido em um lago artificial do Sudeste brasileiro. Imaturos, fêmeas e machos possuem padrões diferentes quanto à relação peso-comprimento e quanto às variações sazonais do fator de condição, que estão relacionadas às alterações de intensidade da atividade alimentar e ao período reprodutivo. Assim, a relação peso-comprimento e o fator de condição variam de acordo com tempo de introdução, tamanho da população, características dos ecossistemas, as interações intra e interespecíficas e maturidade sexual.The length-weight relationship and condition factor for Cichla kelberi introduced in an artificial lake in southeastern Brazil were analyzed. By studying separately the male, female and immatureindividuals, different length-weight patterns were found to happen among them. The same happened when distinct seasonal variations were compared. They are related to feeding alterations and the reproductive periods. The length-weight relationship and condition factor for these fishes vary in accordance with the time of introduction, population size, the characteristics of the ecosystem, sexual maturity, as well as the intra- and interspecific interactions.
Energy Technology Data Exchange (ETDEWEB)
Barbosa, Diego R.; Silva, Alessandro L. da; Luciano, Edson Jose Rezende; Nepomuceno, Leonardo [Universidade Estadual Paulista (UNESP), Bauru, SP (Brazil). Dept. de Engenharia Eletrica], Emails: diego_eng.eletricista@hotmail.com, alessandrolopessilva@uol.com.br, edson.joserl@uol.com.br, leo@feb.unesp.br
2009-07-01
Problems of DC Optimal Power Flow (OPF) have been solved by various conventional optimization methods. When the modeling of DC OPF involves discontinuous functions or not differentiable, the use of solution methods based on conventional optimization is often not possible because of the difficulty in calculating the gradient vectors at points of discontinuity/non-differentiability of these functions. This paper proposes a method for solving the DC OPF based on Genetic Algorithms (GA) with real coding. The proposed GA has specific genetic operators to improve the quality and viability of the solution. The results are analyzed for an IEEE test system, and its solutions are compared, when possible, with those obtained by a method of interior point primal-dual logarithmic barrier. The results highlight the robustness of the method and feasibility of obtaining the solution to real systems.
Directory of Open Access Journals (Sweden)
Huang Chen-Cheng
2012-07-01
Full Text Available Abstract Background Mycobacteria can be quickly and simply identified by PCR restriction-enzyme analysis (PRA, but misidentification can occur because of similarities in band sizes that are critical for discriminating among species. Capillary electrophoresis can provide computer-aided band discrimination. The aim of this research was to develop an algorithm for identifying mycobacteria by combined rpoB duplex PRA (DPRA and hsp65 PRA with capillary electrophoresis. Results Three hundred and seventy-six acid-fast bacillus smear-positive BACTEC cultures, including 200 Mycobacterium tuberculosis complexes (MTC and 176 non-tuberculous mycobacteria (NTM were analyzed. With combined hsp65 and rpoB DPRA, the accuracy rate was 100% (200 isolates for the MTC and 91.4% (161 isolates for the NTM. Among the discordant results (8.6% for the NTM, one isolate of Mycobacterial species and an isolate of M. flavescens were found as new sub-types in hsp65 PRA. Conclusions This effective and novel identification algorithm using combined rpoB DPRA and hsp65 PRA with capillary electrophoresis can rapidly identify mycobacteria and find new sub-types in hsp65 PRA. In addition, it is complementary to 16 S rDNA sequencing.
A Fast Fractional Difference Algorithm
DEFF Research Database (Denmark)
Jensen, Andreas Noack; Nielsen, Morten Ørregaard
We provide a fast algorithm for calculating the fractional difference of a time series. In standard implementations, the calculation speed (number of arithmetic operations) is of order T 2, where T is the length of the time series. Our algorithm allows calculation speed of order T logT . For mode......We provide a fast algorithm for calculating the fractional difference of a time series. In standard implementations, the calculation speed (number of arithmetic operations) is of order T 2, where T is the length of the time series. Our algorithm allows calculation speed of order T log...
Institute of Scientific and Technical Information of China (English)
黄宁宁; 贾振红; 杨杰; 庞韶宁
2011-01-01
基于纹理图像的特征,提出了基于灰度共生矩阵(GLCM)和快速极大似然估计(EM)算法相结合的纹理图像分割新算法,为了获得较好的纹理图像分割结果该算法采用灰度共生矩阵的三个常用特征并在四个方向上求平均,从而克服了方向的影响.采用欧式距离度量函数求得两特征向量的距离.通过用改进EM算法对距离矩阵进行聚类,得到纹理图像的初始分割结果,最后用形态学的方法实现对纹理图像边界的精确定位.
基于朴素贝叶斯的EM缺失数据填充算法%EM algorithm to implement missing values based on Nalve Bayesian
Institute of Scientific and Technical Information of China (English)
邹薇; 王会进
2011-01-01
Dataset with missing values is quite common in real applications. It is a big problem of data pretreatment, and handling missing values has become a research hot issue. EM chooses the center of cluster randomly leading to cluster irregularly, so this pape%实际应用中大量的不完整的数据集，造成了数据中信息的丢失和分析的不方便，所以对缺失数据的处理已经成为目前分类领域研究的热点。由于EM方法随机选取初始代表簇中心会导致聚类不稳定，本文使用朴素贝叶斯算法的分类结果作为EM算法的初始使用范围，然后按E步M步反复求精，利用得到的最大化值填充缺失数据。实验结果表明，本文的算法加强了聚类的稳定性，具有更好的数据填充效果。
Energy Technology Data Exchange (ETDEWEB)
Almeida, Adino Americo Heimlich
2009-07-01
Graphics Processing Units (GPU) are high performance co-processors intended, originally, to improve the use and quality of computer graphics applications. Since researchers and practitioners realized the potential of using GPU for general purpose, their application has been extended to other fields out of computer graphics scope. The main objective of this work is to evaluate the impact of using GPU in two typical problems of Nuclear area. The neutron transport simulation using Monte Carlo method and solve heat equation in a bi-dimensional domain by finite differences method. To achieve this, we develop parallel algorithms for GPU and CPU in the two problems described above. The comparison showed that the GPU-based approach is faster than the CPU in a computer with two quad core processors, without precision loss. (author)
Variable length representation in evolutionary electronics.
Zebulum, R S; Pacheco, M A; Vellasco, M
2000-01-01
This work investigates the application of variable length representation (VLR) evolutionary algorithms (EAs) in the field of Evolutionary Electronics. We propose a number of VLR methodologies that can cope with the main issues of variable length evolutionary systems. These issues include the search for efficient ways of sampling a genome space with varying dimensionalities, the task of balancing accuracy and parsimony of the solutions, and the manipulation of non-coding segments. We compare the performance of three proposed VLR approaches to sample the genome space: Increasing Length Genotypes, Oscillating Length Genotypes, and Uniformly Distributed Initial Population strategies. The advantages of reusing genetic material to replace non-coding segments are also emphasized in this work. It is shown, through examples in both analog and digital electronics, that the variable length genotype's representation is natural to this particular domain of application. A brief discussion on biological genome evolution is also provided.
Directory of Open Access Journals (Sweden)
Mitsuru Ogata
2005-03-01
Full Text Available OBJECTIVE: To compare the efficacy of three conditions of image interpretation for radiographic root measurements and calculating the intra-observer reproducibility of the measurements. MATERIAL AND METHODS: Thirty intra-operative periapical radiographs of maxillary central and lateral incisors were measured, in mm, from the tip of the file to the radiographic apex, using a caliper. Three separate measurements were made of the 30 radiographs. The three measurements for each tooth were averaged and the mean used for further calculations. After a 12-day period, the measurements were repeated. The three experimental viewing conditions used: 1 standard viewbox without masking of background light around the radiograph and without magnification (Visual; 2 standard viewbox with use of a magnifying lens of 2.5x and with background light masked (Magnification; and 3 viewer device that restricts room lighting and enlarges the image by a magnifying lens of 1.75x (Viewer. The mean and standard deviation of the measurements were calculated and used for descriptive analysis. Two-way analysis of variance (ANOVA was used to evaluate intra-observer and inter-method agreement of the measurements. The measurement error was estimated by Dalhberg's formula. RESULTS: The ANOVA showed no significant differences between measurement sessions, viewing methods, or interaction between observation session and method (p>0.05. The intra-observer measurement error was 0.02 mm for Visual and the Magnification methods and 0.01 mm for the Viewer. CONCLUSION: There does not seem to be any advantage in using viewbox masking or magnification for measuring the distance between the end of the endodontic file and the root apex in maxillary incisors.OBJETIVO: Comparar a eficácia de três condições de interpretação radiográfica em odontometria e avaliar a concordância intra-observador. MATERIAL E MÉTODO: Trinta radiografias periapicais de incisivos central e lateral superiores
Methodology and basic algorithms of the Livermore Economic Modeling System
Energy Technology Data Exchange (ETDEWEB)
Bell, R.B.
1981-03-17
The methodology and the basic pricing algorithms used in the Livermore Economic Modeling System (EMS) are described. The report explains the derivations of the EMS equations in detail; however, it could also serve as a general introduction to the modeling system. A brief but comprehensive explanation of what EMS is and does, and how it does it is presented. The second part examines the basic pricing algorithms currently implemented in EMS. Each algorithm's function is analyzed and a detailed derivation of the actual mathematical expressions used to implement the algorithm is presented. EMS is an evolving modeling system; improvements in existing algorithms are constantly under development and new submodels are being introduced. A snapshot of the standard version of EMS is provided and areas currently under study and development are considered briefly.
Speed-up for N-FINDR algorithm
Institute of Scientific and Technical Information of China (English)
WANG Li-guo; ZHANG Ye
2008-01-01
N-FINDR is a very popular algorithm of endmember (EM) extraction for its automated property and high efficiency. Unfortunately, innumerable volume calculation, initial random selection of EMs and blind searching for EMs lead to low speed of the algorithm and limit the applications of the algorithm. So in this paper two measures are proposed to speed up the algorithm. One of the measures is substituting distance calculation for volume calculation. Thus the avoidance of volume calculation greatly decreases the computational cost. The other measure is resorting dataset in terms of pixel purity hkelihood based on pixel purity index (PPI) concept. Then, initial EMs can be selected well-founded and a fast searching for EMs is achieved. Numerical experi-ments show that the two measures speed up the original algorithm hundreds of times as the number of EMs is more than ten.
Directory of Open Access Journals (Sweden)
Giovanni Amori
1986-12-01
Full Text Available Abstract In Italy there are two species of <em>Apodemus> (<em>Sylvaemus>: <em>Apodemus sylvaticusem> on the mainland and the main island, and <em>Apodemus flavicollisem> only on the mainland. The trend of some morphometric characters of the skull (incisive foramen length - FI; interorbital breadth = IO; length of palatal bridge = PP; upper alveolar length = $M^1M^3$ was analized and some theoretical models verified for <em>A. sylvaticusem>. If one considers the sympatric population of <em>A. sylvaticusem> and <em>A. flavicollisem> simultaneously the characters PP, IO and $M^1M^3$ appear significantly isometric being directly correlated ($P leq O.O1$, while FI character results allometric with respect to the previous ones, as expected. If one considers the sympatric populations of each of the species separately, the scenario is different. For <em>A. sylvaticusem> only PP and $M^1M^3$ are isometric ($P leq 0.05$. For <em>A. flavicollisem> only $M^1M^3$ and FI appear to be correlated, although not as significantly as for <em>A. sylvaticusem> ($P le 0.05$; one tail. The insular populations of <em>A. sylvaticusem> do not show significant correlations, except for FI and $M^1M^3$ ($P le 0.05$. On the contrary, considering all populations, sympatric and allopatric, of <em>A. sylvaticusem> at the same time are significant correlations ($P le 0.05$ in all combinations of characters, except for those involving the IO. We suggest that the isometric relations in sympatric assemblages are confined within a morphological range available to the genus <em>Apodemus>. In such a space, the two species are split in two different and innerly homogeneous distributions. We found no evidence to confirm the niche variation hypothesis. On the contrary, the variability expressed as SO or CV's appears higher in the sympatric populations than in the allopatric ones, for three of the four characters, confirming previous results
Minimum Length - Maximum Velocity
Panes, Boris
2011-01-01
We study a framework where the hypothesis of a minimum length in space-time is complemented with the notion of reference frame invariance. It turns out natural to interpret the action of the obtained reference frame transformations in the context of doubly special relativity. As a consequence of this formalism we find interesting connections between the minimum length properties and the modified velocity-energy relation for ultra-relativistic particles. For example we can predict the ratio between the minimum lengths in space and time using the results from OPERA about superluminal neutrinos.
Directory of Open Access Journals (Sweden)
Luciana Kazue Otutumi
2008-07-01
Full Text Available O trabalho objetivou avaliar o efeito do probiótico associado a diferentes níveis de proteína bruta (PB sobre o comprimento e a morfometria da mucosa do intestino delgado de codornas de corte. Foram utilizadas 2.304 codornas de corte, distribuídas em umdelineamento experimental inteiramente casualizado em esquema fatorial 2 x 4 (com e sem probiótico; quatro níveis de PB – 15, 20, 25 e 30%, com duas repetições por tratamento, em dois períodos experimentais. Aos sete, 14, 21 e 35 dias de idade, foram abatidas duas aves de cada repetição para avaliação do comprimento do intestino delgado (CID e a morfometria da mucosa do duodeno e íleo. O probiótico não influenciou o CID e a morfometria da mucosa do intestino delgado. O comprimento do intestino aumentou de maneira linear com a elevação dos níveis de PB aos sete, 14 e 21 dias, e a morfometria da mucosa aumentou de forma linear somente para altura vilo do íleo. Pode-se concluir que, nas condições ambientais em que as codornas foram criadas, apenas o nível de proteína influenciou o comprimento do intestino delgado e a altura de vilo do íleo, não sendoobservado efeito do probiótico sobre estes parâmetros.The aim of this study was to evaluate the effect of probiotic associated to different levels of crude protein (CP on thelength and mucous morphometry of the small intestine of meat quails. The study used 2,304 meat quails, distributed in a completely randomized experimental design in a 2 x 4 factorial scheme (with and without probiotic; four levels of CP – 15, 20, 25 and 30%, withtwo replications per treatment, in two experimental periods. At seven, 14, 21 and 35 days of age, two quails of each replication were slaughtered in order to evaluate the length of the small intestine (LSI, as well as duodenum and ileum mucous morphometry. LSI and smallintestine mucous morphometry were not influenced by probiotic. Intestine length increased in a linear fashion with the increase
Time-Dependent Damage Investigation of Rock Mass in an <em>In> em>Situ> Experimental Tunnel
Directory of Open Access Journals (Sweden)
Jing Chen
2012-08-01
Full Text Available In underground tunnels or caverns, time-dependent deformation or failure of rock mass, such as extending cracks, gradual rock falls, <em>etc>., are a costly irritant and a major safety concern if the time-dependent damage of surrounding rock is serious. To understand the damage evolution of rock mass in underground engineering, an <em>in situem> experimental testing was carried out in a large belowground tunnel with a scale of 28.5 m in width, 21 m in height and 352 m in length. The time-dependent damage of rock mass was detected in succession by an ultrasonic wave test after excavation. The testing results showed that the time-dependent damage of rock mass could last a long time, <em>i.e.>, nearly 30 days. Regression analysis of damage factors defined by wave velocity, resulted in the time-dependent evolutional damage equation of rock mass, which corresponded with logarithmic format. A damage viscoelastic-plastic model was developed to describe the exposed time-dependent deterioration of rock mass by field test, such as convergence of time-dependent damage, deterioration of elastic modules and logarithmic format of damage factor. Furthermore, the remedial measures for damaged surrounding rock were discussed based on the measured results and the conception of damage compensation, which provides new clues for underground engineering design.
Telomere length and depression
DEFF Research Database (Denmark)
Wium-Andersen, Marie Kim; Ørsted, David Dynnes; Rode, Line
2016-01-01
BACKGROUND: Depression has been cross-sectionally associated with short telomeres as a measure of biological age. However, the direction and nature of the association is currently unclear. AIMS: We examined whether short telomere length is associated with depression cross-sectionally as well...... as prospectively and genetically. METHOD: Telomere length and three polymorphisms, TERT, TERC and OBFC1, were measured in 67 306 individuals aged 20-100 years from the Danish general population and associated with register-based attendance at hospital for depression and purchase of antidepressant medication....... RESULTS: Attendance at hospital for depression was associated with short telomere length cross-sectionally, but not prospectively. Further, purchase of antidepressant medication was not associated with short telomere length cross-sectionally or prospectively. Mean follow-up was 7.6 years (range 0...
Myofilament length dependent activation
Energy Technology Data Exchange (ETDEWEB)
de Tombe, Pieter P.; Mateja, Ryan D.; Tachampa, Kittipong; Mou, Younss Ait; Farman, Gerrie P.; Irving, Thomas C. (IIT); (Loyola)
2010-05-25
The Frank-Starling law of the heart describes the interrelationship between end-diastolic volume and cardiac ejection volume, a regulatory system that operates on a beat-to-beat basis. The main cellular mechanism that underlies this phenomenon is an increase in the responsiveness of cardiac myofilaments to activating Ca{sup 2+} ions at a longer sarcomere length, commonly referred to as myofilament length-dependent activation. This review focuses on what molecular mechanisms may underlie myofilament length dependency. Specifically, the roles of inter-filament spacing, thick and thin filament based regulation, as well as sarcomeric regulatory proteins are discussed. Although the 'Frank-Starling law of the heart' constitutes a fundamental cardiac property that has been appreciated for well over a century, it is still not known in muscle how the contractile apparatus transduces the information concerning sarcomere length to modulate ventricular pressure development.
Kleinberg, Jon
2006-01-01
Algorithm Design introduces algorithms by looking at the real-world problems that motivate them. The book teaches students a range of design and analysis techniques for problems that arise in computing applications. The text encourages an understanding of the algorithm design process and an appreciation of the role of algorithms in the broader field of computer science.
Wang, Lui; Bayer, Steven E.
1991-01-01
Genetic algorithms are mathematical, highly parallel, adaptive search procedures (i.e., problem solving methods) based loosely on the processes of natural genetics and Darwinian survival of the fittest. Basic genetic algorithms concepts are introduced, genetic algorithm applications are introduced, and results are presented from a project to develop a software tool that will enable the widespread use of genetic algorithm technology.
A Characteristic Particle Length
Roberts, Mark D
2015-01-01
It is argued that there are characteristic intervals associated with any particle that can be derived without reference to the speed of light $c$. Such intervals are inferred from zeros of wavefunctions which are solutions to the Schr\\"odinger equation. The characteristic length is $\\ell=\\beta^2\\hbar^2/(8Gm^3)$, where $\\beta=3.8\\dots$; this length might lead to observational effects on objects the size of a virus.
Demaison, Jean; Császár, Attila G.
2012-09-01
Based on a sample of 38 molecules, 47 accurate equilibrium CO bond lengths have been collected and analyzed. These ultimate experimental (reEX), semiexperimental (reSE), and Born-Oppenheimer (reBO) equilibrium structures are compared to reBO estimates from two lower-level techniques of electronic structure theory, MP2(FC)/cc-pVQZ and B3LYP/6-311+G(3df,2pd). A linear relationship is found between the best equilibrium bond lengths and their MP2 or B3LYP estimates. These (and similar) linear relationships permit to estimate the CO bond length with an accuracy of 0.002 Å within the full range of 1.10-1.43 Å, corresponding to single, double, and triple CO bonds, for a large number of molecules. The variation of the CO bond length is qualitatively explained using the Atoms in Molecules method. In particular, a nice correlation is found between the CO bond length and the bond critical point density and it appears that the CO bond is at the same time covalent and ionic. Conditions which permit the computation of an accurate ab initio Born-Oppenheimer equilibrium structure are discussed. In particular, the core-core and core-valence correlation is investigated and it is shown to roughly increase with the bond length.
Observations on oesophageal length.
Kalloor, G J; Deshpande, A H; Collis, J L
1976-01-01
The subject of oesophageal length is discussed. The great variations in the length of the oesophagus in individual patients is noted, and the practical use of its recognition in oesophageal surgery is stressed. An apprasial of the various methods available for this measurement is made; this includes the use of external chest measurement, endoscopic measurement, and the measurement of the level of the electrical mucosal potential change. Correlative studies of these various methods are made, and these show a very high degree of significance. These studies involved simultaneous measurement of external and internal oesophageal length in 26 patients without a hiatal hernia or gastro-oesophageal length in 26 patients without a hiatal hernia or gastro-oesophageal reflux symptoms, 42 patients with sliding type hiatal hernia, and 17 patients with a peptic stricture in association with hiatal hernia. The method of measuring oesophageal length by the use of the external chest measurement, that is, the distance between the lower incisor teeth and the xiphisternum, measured with the neck fully extended and the patient lying supine, is described in detail, its practical application in oesophageal surgery is illustrated, and its validity tested by internal measurements. The findings of this study demonstrate that the external chest measurement provides a mean of assessing the true static length of the oesophagus, corrected for the size of the individual. Images PMID:941114
Fast Local Computation Algorithms
Rubinfeld, Ronitt; Vardi, Shai; Xie, Ning
2011-01-01
For input $x$, let $F(x)$ denote the set of outputs that are the "legal" answers for a computational problem $F$. Suppose $x$ and members of $F(x)$ are so large that there is not time to read them in their entirety. We propose a model of {\\em local computation algorithms} which for a given input $x$, support queries by a user to values of specified locations $y_i$ in a legal output $y \\in F(x)$. When more than one legal output $y$ exists for a given $x$, the local computation algorithm should output in a way that is consistent with at least one such $y$. Local computation algorithms are intended to distill the common features of several concepts that have appeared in various algorithmic subfields, including local distributed computation, local algorithms, locally decodable codes, and local reconstruction. We develop a technique, based on known constructions of small sample spaces of $k$-wise independent random variables and Beck's analysis in his algorithmic approach to the Lov{\\'{a}}sz Local Lemma, which und...
Directory of Open Access Journals (Sweden)
Claudionor Ribeiro da Silva
2010-07-01
Full Text Available O objetivo deste trabalho é a extração semiautomática de estradas vicinais. Este estudo é dividido em duas fases distintas. Na primeira fase é proposto um método para determinar larguras de estradas; na segunda fase é proposta uma função de aptidão para algoritmos genéticos que possibilita a detecção de segmentos candidatos a eixo deestradas vicinais. Três imagens digitais são usadas na realização dos experimentos. Para o estudo, a validação dos resultados obtidos foi realizada a partir de uma imagem de referência. A imagem de referência foi criada por meio de vetorização manual. O julgamento da acurácia foi computado com base nos índices: completeza, correção eRMS. Os resultados obtidos apontam a metodologia proposta como promissora. The aim objective of this paper is to present a semi-automatic extraction of local roads. The research is divided in two different phases. In the first one, a method to determine road width is proposed; in the second one, a fitness function for genetic algorithms is proposed. The referred function makes possible the detection of candidate segments for local roads axis. Three digital images are used in conducting the experiments. For the study, the validation of the obtained results was accomplished based on a reference image. The reference image was created through manualvectoring, and an accuracy evaluation was computed based on the following indexes: completeness, correctness and RMS. The obtained results point out the proposed methodology as promising.
Directory of Open Access Journals (Sweden)
Régis Eric Maia Barros
2010-06-01
Full Text Available OBJECTIVE: Characterize and compare acute psychiatric admissions to the psychiatric wards of a general hospital (22 beds, a psychiatric hospital (80 and of an emergency psychiatry unit (6. METHOD: Survey of the ratios and shares of the demographic, diagnostic and hospitalization variables involved in all acute admissions registered in a catchment area in Brazil between 1998 and 2004. RESULTS: From the 11,208 admissions, 47.8% of the patients were admitted to a psychiatric hospital and 14.1% to a general hospital. The emergency psychiatry unit accounted for 38.1% of all admissions during the period, with a higher variability in occupancy rate and bed turnover during the years. Around 80% of the hospital stays lasted less than 20 days and in almost half of these cases, patients were discharged in 2 days. Although the total number of admissions remained stable during the years, in 2004, a 30% increase was seen compared to 2003. In 2004, bed turnover and occupancy rate at the emergency psychiatry unit increased. CONCLUSION: The increase in the number of psychiatric admissions in 2004 could be attributed to a lack of new community-based services available in the area beginning in 1998. Changes in the health care network did affect the emergency psychiatric service and the limitations of the community-based network could influence the rate of psychiatric admissions.OBJETIVO: Caracterizar e comparar internações psiquiátricas agudas em alas psiquiátricas no hospital geral (22 leitos, hospital psiquiátrico (80 e emergência psiquiátrica (6. MÉTODO: Foram analisadas todas as internações agudas entre 1998 e 2004 na região do estudo, com razões e proporções de variáveis demográficas, diagnósticas e das hospitalizações. RESULTADOS: Das 11.208 internações, 47,8% foram no hospital psiquiátrico e 14,1% no hospital geral. A emergência psiquiátrica realizou 38,1% das internações no período, com grande variabilidade da taxa de ocupa
Joux, Antoine
2009-01-01
Illustrating the power of algorithms, Algorithmic Cryptanalysis describes algorithmic methods with cryptographically relevant examples. Focusing on both private- and public-key cryptographic algorithms, it presents each algorithm either as a textual description, in pseudo-code, or in a C code program.Divided into three parts, the book begins with a short introduction to cryptography and a background chapter on elementary number theory and algebra. It then moves on to algorithms, with each chapter in this section dedicated to a single topic and often illustrated with simple cryptographic applic
Blind sequence-length estimation of low-SNR cyclostationary sequences
CSIR Research Space (South Africa)
Vlok, JD
2014-06-01
Full Text Available Several existing direct-sequence spread spectrum (DSSS) detection and estimation algorithms assume prior knowledge of the symbol period or sequence length, although very few sequence-length estimation techniques are available in the literature...
Directory of Open Access Journals (Sweden)
Wentian eLi
2014-11-01
Full Text Available Power-law distributions are the main functional form forthe distribution of repeat size and repeat copy number in the human genome. When the genome is broken into fragments for sequencing, the limited size offragments and reads may prevent an unique alignment of repeatsequences to the reference sequence. Repeats in the human genome canbe as long as $10^4$ bases, or $10^5-10^6$ bases when allowing for mismatches between repeat units. Sequence reads from these regions are therefore unmappable when the read length is in the range of $10^3$ bases.With the read length of exactly 1000 bases, slightly more than 1% of theassembled genome, and slightly less than 1% of the 1kbreads, are unmappable, excluding the unassembled portion of the humangenome (8% in GRCh37. The slow decay (long tail ofthe power-law function implies a diminishing return in convertingunmappable regions/reads to become mappable with the increase of theread length, with the understanding that increasing read length willalways move towards the direction of 100% mappability.
DEFF Research Database (Denmark)
Kimura, Masayuki; Hjelmborg, Jacob V B; Gardner, Jeffrey P
2008-01-01
telomeres predicted the death of the first co-twin better than the mTRFL did (mTRFL: 0.56, 95% confidence interval (CI): 0.49, 0.63; mTRFL(50): 0.59, 95% CI: 0.52, 0.66; mTRFL(25): 0.59, 95% CI: 0.52, 0.66; MTRFL: 0.60, 95% CI: 0.53, 0.67). The telomere-mortality association was stronger in years 3-4 than......Leukocyte telomere length, representing the mean length of all telomeres in leukocytes, is ostensibly a bioindicator of human aging. The authors hypothesized that shorter telomeres might forecast imminent mortality in elderly people better than leukocyte telomere length. They performed mortality...... analysis in 548 same-sex Danish twins (274 pairs) aged 73-94 years, of whom 204 pairs experienced the death of one or both co-twins during 9-10 years of follow-up (1997-2007). From the terminal restriction fragment length (TRFL) distribution, the authors obtained the mean TRFL (mTRFL) and the mean values...
Hougardy, Stefan
2016-01-01
Algorithms play an increasingly important role in nearly all fields of mathematics. This book allows readers to develop basic mathematical abilities, in particular those concerning the design and analysis of algorithms as well as their implementation. It presents not only fundamental algorithms like the sieve of Eratosthenes, the Euclidean algorithm, sorting algorithms, algorithms on graphs, and Gaussian elimination, but also discusses elementary data structures, basic graph theory, and numerical questions. In addition, it provides an introduction to programming and demonstrates in detail how to implement algorithms in C++. This textbook is suitable for students who are new to the subject and covers a basic mathematical lecture course, complementing traditional courses on analysis and linear algebra. Both authors have given this "Algorithmic Mathematics" course at the University of Bonn several times in recent years.
Abrams, D.; Williams, C.
1999-01-01
This thesis describes several new quantum algorithms. These include a polynomial time algorithm that uses a quantum fast Fourier transform to find eigenvalues and eigenvectors of a Hamiltonian operator, and that can be applied in cases for which all know classical algorithms require exponential time.
Tel, G.
1993-01-01
We define the notion of total algorithms for networks of processes. A total algorithm enforces that a "decision" is taken by a subset of the processes, and that participation of all processes is required to reach this decision. Total algorithms are an important building block in the design of distri
Directory of Open Access Journals (Sweden)
Min Huang
2012-05-01
Full Text Available An apoptosis correlated molecule—protein Latcripin-1 of <em>Lentinula> edodesem> C_{91}_{-}_{3}—was expressed and characterized in <em>Pichia pastorisem> GS115. The total RNA was obtained from <em>Lentinula edodesem> C_{91–3}. According to the transcriptome, the full-length gene of Latcripin-1 was isolated with 3'-Full Rapid Amplification of cDNA Ends (RACE and 5'-Full RACE methods. The full-length gene was inserted into the secretory expression vector pPIC9K. The protein Latcripin-1 was expressed in <em>Pichia pastorisem> GS115 and analyzed by Sodium Dodecylsulfonate Polyacrylate Gel Electrophoresis (SDS-PAGE and Western blot. The Western blot showed that the protein was expressed successfully. The biological function of protein Latcripin-1 on A549 cells was studied with flow cytometry and the 3-(4,5-Dimethylthiazol-2-yl-2,5-Diphenyl-tetrazolium Bromide (MTT method. The toxic effect of protein Latcripin-1 was detected with the MTT method by co-culturing the characterized protein with chick embryo fibroblasts. The MTT assay results showed that there was a great difference between protein Latcripin-1 groups and the control group (<em>p em>< 0.05. There was no toxic effect of the characterized protein on chick embryo fibroblasts. The flow cytometry showed that there was a significant difference between the protein groups of interest and the control group according to apoptosis function (<em>p em>< 0.05. At the same time, cell ultrastructure observed by transmission electron microscopy supported the results of flow cytometry. The work demonstrates that protein Latcripin-1 can induce apoptosis of human lung cancer cells A549 and brings new insights into and advantages to finding anti-tumor proteins.
Martin-Fernandez, Manuel; Revuelta, Javier
2017-01-01
This study compares the performance of two estimation algorithms of new usage, the Metropolis-Hastings Robins-Monro (MHRM) and the Hamiltonian MCMC (HMC), with two consolidated algorithms in the psychometric literature, the marginal likelihood via EM algorithm (MML-EM) and the Markov chain Monte Carlo (MCMC), in the estimation of multidimensional…
Relativistic length agony continued
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Redžić D.V.
2014-01-01
Full Text Available We made an attempt to remedy recent confusing treatments of some basic relativistic concepts and results. Following the argument presented in an earlier paper (Redžić 2008b, we discussed the misconceptions that are recurrent points in the literature devoted to teaching relativity such as: there is no change in the object in Special Relativity, illusory character of relativistic length contraction, stresses and strains induced by Lorentz contraction, and related issues. We gave several examples of the traps of everyday language that lurk in Special Relativity. To remove a possible conceptual and terminological muddle, we made a distinction between the relativistic length reduction and relativistic FitzGerald-Lorentz contraction, corresponding to a passive and an active aspect of length contraction, respectively; we pointed out that both aspects have fundamental dynamical contents. As an illustration of our considerations, we discussed briefly the Dewan-Beran-Bell spaceship paradox and the ‘pole in a barn’ paradox. [Projekat Ministarstva nauke Republike Srbije, br. 171028
Testing the accuracy of redshift space group finding algorithms
Frederic, J J
1994-01-01
Using simulated redshift surveys generated from a high resolution N-body cosmological structure simulation, we study algorithms used to identify groups of galaxies in redshift space. Two algorithms are investigated; both are friends-of-friends schemes with variable linking lengths in the radial and transverse dimensions. The chief difference between the algorithms is in the redshift linking length. The algorithm proposed by Huchra \\& Geller (1982) uses a generous linking length designed to find ``fingers of god'' while that of Nolthenius \\& White (1987) uses a smaller linking length to minimize contamination by projection. We find that neither of the algorithms studied is intrinsically superior to the other; rather, the ideal algorithm as well as the ideal algorithm parameters depend on the purpose for which groups are to be studied. The Huchra/Geller algorithm misses few real groups, at the cost of including some spurious groups and members, while the Nolthenius/White algorithm misses high velocity d...
Ground Wood Fiber Length Distributions
Lauri Ilmari Salminen; Sari Liukkonen; Alava, Mikko J.
2014-01-01
This study considers ground wood fiber length distributions arising from pilot grindings. The empirical fiber length distributions appear to be independent of wood fiber length as well as feeding velocity. In terms of mathematics the fiber fragment distributions of ground wood pulp combine an exponential distribution for high-length fragments and a power-law distribution for smaller lengths. This implies that the fiber length distribution is influenced by the stone surface. A fragmentation-ba...
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
The search for patterns or motifs in data represents a problem area of key interest to finance and economic researchers. In this paper, we introduce the motif tracking algorithm (MTA), a novel immune inspired (IS) pattern identification tool that is able to identify unknown motifs of a non specified length which repeat within time series data. The power of the algorithm comes from the fact that it uses a small number of parameters with minimal assumptions regarding the data being examined or the underlying motifs. Our interest lies in applying the algorithm to financial time series data to identify unknown patterns that exist. The algorithm is tested using three separate data sets. Particular suitability to financial data is shown by applying it to oil price data. In all cases, the algorithm identifies the presence of a motif population in a fast and efficient manner due to the utilization of an intuitive symbolic representation.The resulting population of motifs is shown to have considerable potential value for other applications such as forecasting and algorithm seeding.
Land-cover classification with an expert classification algorithm using digital aerial photographs
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José L. de la Cruz
2010-05-01
Full Text Available The purpose of this study was to evaluate the usefulness of the spectral information of digital aerial sensors in determining land-cover classification using new digital techniques. The land covers that have been evaluated are the following, (1 bare soil, (2 cereals, including maize (<em>Zea maysem> L., oats (<em>Avena sativaem> L., rye (<em>Secale cereale em>L., wheat (<em>Triticum aestivum em>L. and barley (<em>Hordeun vulgareem> L., (3 high protein crops, such as peas (<em>Pisum sativumem> L. and beans (<em>Vicia fabaem> L., (4 alfalfa (<em>Medicago sativaem> L., (5 woodlands and scrublands, including holly oak (<em>Quercus ilexem> L. and common retama (<em>Retama sphaerocarpaem> L., (6 urban soil, (7 olive groves (<em>Olea europaeaem> L. and (8 burnt crop stubble. The best result was obtained using an expert classification algorithm, achieving a reliability rate of 95%. This result showed that the images of digital airborne sensors hold considerable promise for the future in the field of digital classifications because these images contain valuable information that takes advantage of the geometric viewpoint. Moreover, new classification techniques reduce problems encountered using high-resolution images; while reliabilities are achieved that are better than those achieved with traditional methods.
Alexandre Tachard Passos
2013-01-01
Resumo: Em processamento de linguagem natural, e em aprendizado de máquina em geral, é comum o uso de modelos gráficos probabilísticos (probabilistic graphical models). Embora estes modelos sejam muito convenientes, possibilitando a expressão de relações complexas entre várias variáveis que se deseja prever dado uma sentença ou um documento, algoritmos comuns de aprendizado e de previsão utilizando estes modelos são frequentemente ineficientes. Por isso têm-se explorado recentemente o uso de ...
Network Packet Length Covert Channel Based on Empirical Distribution Function
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Lihua Zhang
2014-06-01
Full Text Available Network packet length covert channel modulates secret message bits onto the packet lengths to transmit secret messages. In this paper, a novel network packet length covert channel is proposed. The proposed scheme is based on the empirical distribution function of packet length series of legitimate traffic. Different from the existing schemes, the lengths of packets which are generated by the covert sender follow the distribution of normal traffic more closely in our scheme. To validate the security of the proposed scheme, the state-of-the-art packet length covert channel detection algorithm is adopted. The experimental results show that the packet length covert channel provides a significant performance improvement in detection resistance meanings
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P. R. Parthasarathy
2001-01-01
Full Text Available The transient solution is obtained analytically using continued fractions for a state-dependent birth-death queue in which potential customers are discouraged by the queue length. This queueing system is then compared with the well-known infinite server queueing system which has the same steady state solution as the model under consideration, whereas their transient solutions are different. A natural measure of speed of convergence of the mean number in the system to its stationarity is also computed.
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Feng Xu
2012-06-01
Full Text Available Phenylalanine ammonia-lyase (PAL is the first key enzyme of the phenypropanoid pathway. A full-length cDNA of <em>PAL> gene was isolated from <em>Juglans regiaem> for the first time, and designated as <em>JrPAL>. The full-length cDNA of the <em>JrPAL> gene contained a 1935bp open reading frame encoding a 645-amino-acid protein with a calculated molecular weight of about 70.4 kD and isoelectric point (pI of 6.7. The deduced JrPAL protein showed high identities with other plant PALs. Molecular modeling of JrPAL showed that the 3D model of JrPAL was similar to that of PAL protein from <em>Petroselinum crispumem> (PcPAL, implying that JrPAL may have similar functions with PcPAL. Phylogenetic tree analysis revealed that JrPAL shared the same evolutionary ancestor of other PALs and had a closer relationship with other angiosperm species. Transcription analysis revealed that <em>JrPAL> was expressed in all tested tissues including roots, stems, and leaves, with the highest transcription level being found in roots. Expression profiling analyses by real-time PCR revealed that <em>JrPAL> expression was induced by a variety of abiotic and biotic stresses, including UV-B, wounding, cold, abscisic acid and salicylic acid.
Decoding Interleaved Gabidulin Codes using Alekhnovich's Algorithm
DEFF Research Database (Denmark)
Puchinger, Sven; Müelich, Sven; Mödinger, David
2017-01-01
We prove that Alekhnovich's algorithm can be used for row reduction of skew polynomial matrices. This yields an O(ℓ3n(ω+1)/2log(n)) decoding algorithm for ℓ-Interleaved Gabidulin codes of length n, where ω is the matrix multiplication exponent.......We prove that Alekhnovich's algorithm can be used for row reduction of skew polynomial matrices. This yields an O(ℓ3n(ω+1)/2log(n)) decoding algorithm for ℓ-Interleaved Gabidulin codes of length n, where ω is the matrix multiplication exponent....
Unsupervised Classification of SAR Images using Hierarchical Agglomeration and EM
Kayabol, K.; Krylov, V.; Zerubia, J.; Salerno, E.; Cetin, A.E.; Salvetti, O.
2012-01-01
We implement an unsupervised classification algorithm for high resolution Synthetic Aperture Radar (SAR) images. The foundation of algorithm is based on Classification Expectation-Maximization (CEM). To get rid of two drawbacks of EM type algorithms, namely the initialization and the model order sel
Effect of Dieckol, a Component of <em>Ecklonia cavaem>, on the Promotion of Hair Growth
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Sang-Cheol Kim
2012-05-01
Full Text Available This study was conducted to evaluate the effect of <em>Ecklonia cavaem>, a marine alga native to Jeju Island in Korea, on the promotion of hair growth. When vibrissa follicles were cultured in the presence of <em>E. cavaem> enzymatic extract (which contains more than 35% of dieckol for 21 days, <em>E. cavaem> enzymatic extract increased hair-fiber length. In addition, after topical application of the 0.5% <em>E. cavaem> enzymatic extract onto the back of C57BL/6 mice, anagen progression of the hair-shaft was induced. The treatment with <em>E. cavaem> enzymatic extract resulted in the proliferation of immortalized vibrissa dermal papilla cells (DPC. Especially, dieckol, among the isolated compounds from the <em>E. cavaem> enzymatic extract, showed activity that increased the proliferation of DPC. When NIH3T3 fibroblasts were treated with the <em>E. cavaem> enzymatic extract and the isolated compounds from the <em>E. cava> enzymatic extract, the <em>E. cavaem> enzymatic extract increased the proliferation of NIH3T3 fibroblasts, but the isolated compounds such as eckol, dieckol, phloroglucinol and triphlorethol-A did not affect the proliferation of NIH3T3 fibroblasts. On the other hand, the <em>E. cavaem> enzymatic extract and dieckol significantly inhibited 5α-reductase activity. These results suggest that dieckol from <em>E. cavaem> can stimulate hair growth by the proliferation of DPC and/or the inhibition of 5α-reductase activity.
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Juliana Savini Wey Berti
2012-08-01
Full Text Available OBJETIVO: Embora a hiperinsuflação manual (HM seja largamente usada para a remoção de secreções pulmonares, não há evidências para sua recomendação como rotina na prática clínica. O objetivo do estudo foi avaliar o efeito da HM combinada com compressão torácica expiratória (CTE na duração de internação em UTI e no tempo de ventilação mecânica (VM em pacientes sob VM. MÉTODOS: Ensaio clínico prospectivo, randomizado e controlado com pacientes de UTI sob VM em um hospital acadêmico terciário entre janeiro de 2004 e janeiro de 2005. Dentre os 49 pacientes que preencheram os critérios do estudo, 24 e 25 foram randomicamente alocados nos grupos fisioterapia respiratória (FR e controle, respectivamente, sendo que 6 e 8 foram retirados do estudo. Durante o período de observação de 5 dias, os pacientes do grupo FR receberam HM combinada com CTE, enquanto os controles receberam o tratamento padrão de enfermagem. RESULTADOS: Os dois grupos apresentaram características basais semelhantes. A intervenção teve efeito positivo na duração de VM, alta da UTI e escore de Murray. Houve diferenças significativas entre os grupos controle e FR em relação à taxa de sucesso no desmame nos dias 2 (0,0% vs. 37,5%, 3 (0,0% vs. 37,5%, 4 (5,3 vs. 37,5% e 5 (15,9% vs. 37,5%, assim como à taxa de alta da UTI nos dias 3 (0% vs. 25%, 4 (0% vs. 31% e 5 (0% vs. 31%. No grupo FR, houve uma melhora significante no escore de Murray no dia 5. CONCLUSÕES: Nossos resultados mostraram que o uso combinado de HM e CTE por 5 dias acelerou o processo de desmame e de alta da UTI.OBJECTIVE: Although manual hyperinflation (MH is widely used for pulmonary secretion clearance, there is no evidence to support its routine use in clinical practice. Our objective was to evaluate the effect that MH combined with expiratory rib cage compression (ERCC has on the length of ICU stay and duration of mechanical ventilation (MV. METHODS: This was a prospective
Wilson, William; Aickelin, Uwe; 10.1007/s11633.008.0032.0
2010-01-01
The search for patterns or motifs in data represents a problem area of key interest to finance and economic researchers. In this paper we introduce the Motif Tracking Algorithm, a novel immune inspired pattern identification tool that is able to identify unknown motifs of a non specified length which repeat within time series data. The power of the algorithm comes from the fact that it uses a small number of parameters with minimal assumptions regarding the data being examined or the underlying motifs. Our interest lies in applying the algorithm to financial time series data to identify unknown patterns that exist. The algorithm is tested using three separate data sets. Particular suitability to financial data is shown by applying it to oil price data. In all cases the algorithm identifies the presence of a motif population in a fast and efficient manner due to the utilisation of an intuitive symbolic representation. The resulting population of motifs is shown to have considerable potential value for other ap...
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Kátia Maehana
2002-04-01
Full Text Available Avaliou-se o efeito da vitamina C e vitamina E na dieta, sobre a ocorrência de ectoparasitas, sobrevivência, peso e comprimento em larvas de tilápia do Nilo, Oreochromis niloticus L. (Perciformes, Cichlidae durante reversão sexual. Larvas com peso médio de 0,01 g e 10 mm de comprimento total foram submetidas a 4 tratamentos: T1= sem adição de vitaminas, T2= 1000 mg de vitamina C, T3= 300 mg de vitamina E e T4= 1000 mg de vitamina C e 300 mg de vitamina E por kg de ração. No início à ocorrência de ectoparasitas diagnosticada foi de 100% (90% Trichodina sp. e 10% infecção mista (Trichodina sp. + monogenético. Ao final do experimento encontrou-se uma diminuição significativa quanto à ocorrência de Trichodina sp. no tratamento com vitamina E (T3 em relação ao sem vitamina (T1. Quanto ao peso e aos comprimentos total e padrão, houve um aumento significativo no tratamento com vitamina E (T3 em relação aos demais. Para sobrevivência o melhor resultado foi no tratamento com vitamina C (T2. Conclui-se, então, que a suplementação de vitamina C na ração foi benéfica em relação à sobrevivência e que a vitamina E possui efeito direto sobre os parâmetros relacionados ao desenvolvimento corpóreo (peso e comprimento, como também sobre a ocorrência de Trichodinas spp.em larvas de tilápia do Nilo, durante o processo de reversão.The effect of the vitamin C and vitamin E in the diet was evaluated on the ectoparasite occurrence, survival, weight and length in Nile tilapia larvae, Oreochromis niloticus L. (Perciformes, Cichlidae, during sexual reversion. Larvae with medium weight of 0,01 g and 10 mm of total length were submitted to four treatments: T1 = without addition of vitamins, T2 = 1000 mg of vitamin C, T3 = 300 mg of vitamin E and T4 = 1000 mg of vitamin C and 300 mg of vitamin E per kg of treat. In the beginning, the occurrence of diagnosed ectoparasite was of 100% (90,0% Trichodina and 10,0% mixed infection. At the
Ground Wood Fiber Length Distributions
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Lauri Ilmari Salminen
2014-01-01
Full Text Available This study considers ground wood fiber length distributions arising from pilot grindings. The empirical fiber length distributions appear to be independent of wood fiber length as well as feeding velocity. In terms of mathematics the fiber fragment distributions of ground wood pulp combine an exponential distribution for high-length fragments and a power-law distribution for smaller lengths. This implies that the fiber length distribution is influenced by the stone surface. A fragmentation-based model is presented that allows reproduction of the empirical results.
Aligning Sequences by Minimum Description Length
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John S. Conery
2008-01-01
Full Text Available This paper presents a new information theoretic framework for aligning sequences in bioinformatics. A transmitter compresses a set of sequences by constructing a regular expression that describes the regions of similarity in the sequences. To retrieve the original set of sequences, a receiver generates all strings that match the expression. An alignment algorithm uses minimum description length to encode and explore alternative expressions; the expression with the shortest encoding provides the best overall alignment. When two substrings contain letters that are similar according to a substitution matrix, a code length function based on conditional probabilities defined by the matrix will encode the substrings with fewer bits. In one experiment, alignments produced with this new method were found to be comparable to alignments from CLUSTALW. A second experiment measured the accuracy of the new method on pairwise alignments of sequences from the BAliBASE alignment benchmark.
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Felipe Naous
2008-05-01
Full Text Available Analisou-se a relação peso-comprimento e o fator de condição de Cichla kelberi introduzido em um lago artificial do Sudeste brasileiro. Imaturos, fêmeas e machos possuem padrões diferentes quanto à relação peso-comprimento e quanto às variações sazonais do fator de condição, que estão relacionadas às alterações de intensidade da atividade alimentar e ao período reprodutivo. Assim, a relação peso-comprimento e o fator de condição variam de acordo com tempo de introdução, tamanho da população, características dos ecossistemas, as interações intra e interespecíficas e maturidade sexual.The length-weight relationship and condition factor for Cichla kelberi introduced in an artificial lake in southeastern Brazil were analyzed. By studying separately the male, female and immature individuals, different length-weight patterns were found to happen among them. The same happened when distinct seasonal variations were compared. They are related to feeding alterations and the reproductive periods. The length-weight relationship and condition factor for these fishes vary in accordance with the time of introduction, population size, the characteristics of the ecosystem, sexual maturity, as well as the intra- and interspecific interactions.
A Scalable Gaussian Process Analysis Algorithm for Biomass Monitoring
Energy Technology Data Exchange (ETDEWEB)
Chandola, Varun [ORNL; Vatsavai, Raju [ORNL
2011-01-01
Biomass monitoring is vital for studying the carbon cycle of earth's ecosystem and has several significant implications, especially in the context of understanding climate change and its impacts. Recently, several change detection methods have been proposed to identify land cover changes in temporal profiles (time series) of vegetation collected using remote sensing instruments, but do not satisfy one or both of the two requirements of the biomass monitoring problem, i.e., {\\em operating in online mode} and {\\em handling periodic time series}. In this paper, we adapt Gaussian process regression to detect changes in such time series in an online fashion. While Gaussian process (GP) have been widely used as a kernel based learning method for regression and classification, their applicability to massive spatio-temporal data sets, such as remote sensing data, has been limited owing to the high computational costs involved. We focus on addressing the scalability issues associated with the proposed GP based change detection algorithm. This paper makes several significant contributions. First, we propose a GP based online time series change detection algorithm and demonstrate its effectiveness in detecting different types of changes in {\\em Normalized Difference Vegetation Index} (NDVI) data obtained from a study area in Iowa, USA. Second, we propose an efficient Toeplitz matrix based solution which significantly improves the computational complexity and memory requirements of the proposed GP based method. Specifically, the proposed solution can analyze a time series of length $t$ in $O(t^2)$ time while maintaining a $O(t)$ memory footprint, compared to the $O(t^3)$ time and $O(t^2)$ memory requirement of standard matrix manipulation based methods. Third, we describe a parallel version of the proposed solution which can be used to simultaneously analyze a large number of time series. We study three different parallel implementations: using threads, MPI, and a
Optimization of inhibitory decision rules relative to length and coverage
Alsolami, Fawaz
2012-01-01
The paper is devoted to the study of algorithms for optimization of inhibitory rules relative to the length and coverage. In contrast with usual rules that have on the right-hand side a relation "attribute ≠ value", inhibitory rules have a relation "attribute = value" on the right-hand side. The considered algorithms are based on extensions of dynamic programming. © 2012 Springer-Verlag.
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Marcio Roberto Moraes de Carvalho
2011-09-01
Full Text Available OBJETIVO: Avaliar associações das complicações pós-operatórias, em pacientes que sobreviveram à sala de operações, com óbito intra-hospitalar e tempo de internação de pacientes submetidos à cirurgia de revascularização miocárdica. MÉTODOS: Foram selecionados aleatoriamente pacientes submetidos à cirurgia de revascularização miocárdica e sobreviventes a sala de operações. Informações sobre complicações e tempo de hospitalização até alta ou óbito foram coletadas retrospectivamente dos prontuários e declarações de óbitos. Estimaram-se segundo presença de complicações, freqüências, letalidade, risco relativo e risco atribuível populacional. As médias de tempo de internação foram comparadas com a estatística de Wald. RESULTADOS: Excluídos prontuários correspondentes aos óbitos da sala de operações e em 86,9% foram identificadas informações sobre complicações, na insuficiência renal houve maior perda de informações (43,9%. Hiperglicemia foi estimada mais freqüente (74,6%, porém com risco atribuível populacional de 31,6%. O risco atribuível populacional foi maior que 60% no baixo débito (77,0%, insuficiência renal (64,3% e parada cardiorrespiratória (60,4%. Identificamos 12 situações de combinações das significâncias dos pares das diferenças entre médias de tempo de internação pós-operatória de acordo com presença de complicações e evolução para alta ou óbito. CONCLUSÃO: São várias complicações identificadas no período pós-operatório da revascularização miocárdica, com freqüências e repercussões diversas sobre letalidade. Controle do miocárdio sob risco de isquemia, estratégias de reposição volêmica, estabilização hemodinâmica, podem ser eficazes no controle da letalidade e tempo de internação.OBJECTIVE: To evaluate associations between post-operative complications in patients who survive surgery and in-hospital deaths and lengths of hospital stays
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Paulo de Tarso Veras Farinatti
2004-10-01
Full Text Available O estudo teve por objetivo verificar a associação de amplitude e cadência do passo com componentes da aptidão muscular (CAM (flexibilidade, força e resistência muscular de membros inferiores, em 25 mulheres de 60 a 86 anos de idade (média = 79 ± 7 anos, fisicamente independentes e cujas condições clínicas não contra-indicassem a realização dos testes propostos. As seguintes variáveis foram estudadas: a amplitude e cadência do passo (AMP e CAP; b peso, estatura e altura sentada em um banco com medida padronizada (44cm; c marcha estacionária de dois minutos (número de repetições (RESISR; d força máxima relativa de extensão de joelhos (carga/peso corporal (FORCAR; e flexibilidade de tornozelo e quadril (graus (FLEXT e FLEXQ. A AMP e CAP foram comparadas com as variáveis dos CAM por meio de técnicas de correlação simples e multivariada. Os resultados indicaram que: a AMP e CAP associaram-se significativamente com o conjunto das variáveis de força e flexibilidade, conforme sugerido pela boa correlação canônica (r can = 0,79; p Este estudio tiene por objetivo verificar la asociación entre la amplitud y cadencia del paso y los componentes de la capacidad muscular (CAM (flexibilidad, fuerza y resistencia muscular de miembros inferiores, en 25 mujeres de 60 a 86 años de edad (promedio = 79 ± 7 anos, físicamente independientes y cuyas condiciones clínicas no impusieron restricciones a la realización de las pruebas sugeridas. Se estudiaron las siguientes variables: a amplitud y cadencia del paso (AMP y CAP; b peso, estatura y altura sentada en un banco con medida estandarizada (44cm; c marcha estacionaria de dos minutos (número de repeticiones (RESISR; d fuerza máxima relativa de extensión de las rodillas (carga / peso corporal (FORCAR; e flexibilidad del tobillo y cuadril (grados (FLEXT y FLEXQ. La AMP y CAP se compararon a las variables de los CAM por medio de técnicas de correlación simple y multivariada. Los
Hromkovic, Juraj
2009-01-01
Explores the science of computing. This book starts with the development of computer science, algorithms and programming, and then explains and shows how to exploit the concepts of infinity, computability, computational complexity, nondeterminism and randomness.
Algorithms For A Fast Universal Noiseless Coder
Yeh, Pen-Shu; Miller, Warner H.; Rice, Robert F.
1994-01-01
Report discusses some algorithms for fast, high-performance universal noiseless coder adaptively generating nearly optimal variable-length codes. Coders based on principles discussed in reports described in "Some Practical Universal Noiseless Coding Techniques" (NPO-18833) and "Optimality of Variable-Length Codes" (NPO-18834). Coding algorithms of present report independently implemented in custom-made very-large-scale integrated-circuit coding modules.
SYMBOLIC VERSOR COMPRESSION ALGORITHM
Institute of Scientific and Technical Information of China (English)
Li Hongbo
2009-01-01
In an inner-product space, an invertible vector generates a reflection with re-spect to a hyperplane, and the Clifford product of several invertible vectors, called a versor in Clifford algebra, generates the composition of the corresponding reflections, which is an orthogonal transformation. Given a versor in a Clifford algebra, finding another sequence of invertible vectors of strictly shorter length but whose Clifford product still equals the input versor, is called versor compression. Geometrically, versor compression is equivalent to decomposing an orthogoual transformation into a shorter sequence of reflections. This paper proposes a simple algorithm of compressing versors of symbolic form in Clifford algebra. The algorithm is based on computing the intersections of lines with planes in the corresponding Grassmann-Cayley algebra, and is complete in the case of Euclidean or Minkowski inner-product space.
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Igor Pavlinić
2008-07-01
Full Text Available Abstract After the discovery of two different phonic types within the common pipistrelle (<em>Pipistrellus pipistrellusem>, mtDNA analysis confirmed the existence of two separate species named as common pipistrelle (<em>P. pipistrellusem> and soprano pipistrelle (<em>P. pygmaeusem>. The discrimination of these two cryptic species using external characters and measures has proved to be somewhat problematic. We examined two colonies of soprano pipistrelle from Donji Miholjac, Croatia. As a result, only two characters proved to be of help for field identification: wing venation (89% of cases and penis morphology and colour for males. The difference in length between the 2^{nd} and 3^{rd} phalanxes of the 3^{rd} finger should be discarded as diagnostic trait between <em>P. pipistrellusem> and <em>P. pygmaeusem> in Croatia. Riassunto Identificazione su basi morfologiche del pipistrello pigmeo (<em>Pipistrellus pygmeausem>, Leach, 1825 in Croazia. A seguito della descrizione di due differenti "tipi fonici" nel pipistrello nano (<em>Pipistrellus pipistrellusem> e della successiva conferma su basi genetiche dell'esistenza di due specie distinte, designate come pipistrello nano (<em>P. pipistrellusem> e pipistrello pigmeo (<em>P. pygmaeusem>, la distinzione delle due specie in base a caratteristiche morfologiche esterne si è dimostrata un problema di difficile soluzione. Sulla base delle caratteristiche distintive e delle differenze biometriche proposte da altri Autori, sono state esaminate due colonie di pipistrello pigmeo a Donji Miholjac, in Croazia. I risultati ottenuti evidenziano che, tra tutti i potenziali caratteri sinora proposti, solo due risultano utili per un'identificazione diretta sul campo: la venatura delle ali, risultata utile alla discriminazione nell'89% degli esemplari analizzati, e la colorazione e morfologia del pene nei maschi. La
Fast algorithm on string cross pattern matching
Institute of Scientific and Technical Information of China (English)
Liu Gongshen; Li Jianhua; Li Shenghong
2005-01-01
Given a set U which is consisted of strings defined on alphabet ∑ , string cross pattern matching is to find all the matches between every two strings in U. It is utilized in text processing like removing the duplication of strings.This paper presents a fast string cross pattern matching algorithm based on extracting high frequency strings. Compared with existing algorithms including single-pattern algorithms and multi-pattern matching algorithms, this algorithm is featured by both low time complexityand low space complexity. Because Chinese alphabet is large and the average length of Chinese words is much short, this algorithm is more suitable to process the text written by Chinese, especially when the size of ∑ is large and the number of strings is far more than the maximum length of strings of set U.
Energy Technology Data Exchange (ETDEWEB)
Albino, Lucas D.; Santos, Gabriela R.; Ribeiro, Victor A.B.; Rodrigues, Laura N., E-mail: lucasdelbem1@gmail.com [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Instituto de Radiologia; Weltman, Eduardo; Braga, Henrique F. [Instituto do Cancer do Estado de Sao Paulo, Sao Paulo, SP (Brazil). Servico de Radioterapia
2013-12-15
The dose accuracy calculated by a treatment planning system is directly related to the chosen algorithm. Nowadays, several calculation doses algorithms are commercially available and they differ in calculation time and accuracy, especially when individual tissue densities are taken into account. The aim of this study was to compare two different calculation algorithms from iPlan®, BrainLAB, in the treatment of pituitary gland tumor with intensity-modulated radiation therapy (IMRT). These tumors are located in a region with variable electronic density tissues. The deviations from the plan with no heterogeneity correction were evaluated. To initial validation of the data inserted into the planning system, an IMRT plan was simulated in a anthropomorphic phantom and the dose distribution was measured with a radiochromic film. The gamma analysis was performed in the film, comparing it with dose distributions calculated with X-ray Voxel Monte Carlo (XVMC) algorithm and pencil beam convolution (PBC). Next, 33 patients plans, initially calculated by PBC algorithm, were recalculated with XVMC algorithm. The treatment volumes and organs-at-risk dose-volume histograms were compared. No relevant differences were found in dose-volume histograms between XVMC and PBC. However, differences were obtained when comparing each plan with the plan without heterogeneity correction. (author)
Reference Gene Selection in the Desert Plant <em>Eremosparton songoricuem>m>
Directory of Open Access Journals (Sweden)
Dao-Yuan Zhang
2012-06-01
Full Text Available <em>Eremosparton songoricum em>(Litv. Vass. (<em>E. songoricumem> is a rare and extremely drought-tolerant desert plant that holds promise as a model organism for the identification of genes associated with water deficit stress. Here, we cloned and evaluated the expression of eight candidate reference genes using quantitative real-time reverse transcriptase polymerase chain reactions. The expression of these candidate reference genes was analyzed in a diverse set of 20 samples including various <em>E. songoricumem> plant tissues exposed to multiple environmental stresses. GeNorm analysis indicated that expression stability varied between the reference genes in the different experimental conditions, but the two most stable reference genes were sufficient for normalization in most conditions.<em> EsEFem> and <em>Esα-TUB> were sufficient for various stress conditions, <em>EsEF> and <em>EsACT> were suitable for samples of differing germination stages, and <em>EsGAPDH>and <em>Es>UBQ em>were most stable across multiple adult tissue samples. The <em>Es18Sem> gene was unsuitable as a reference gene in our analysis. In addition, the expression level of the drought-stress related transcription factor <em>EsDREB2em>> em>verified the utility of<em> E. songoricumem> reference genes and indicated that no single gene was adequate for normalization on its own. This is the first systematic report on the selection of reference genes in <em>E. songoricumem>, and these data will facilitate future work on gene expression in this species.
On constructing symmetrical reversible variable-length codes independent of the Huffman code
Institute of Scientific and Technical Information of China (English)
HUO Jun-yan; CHANG Yi-lin; MA Lin-hua; LUO Zhong
2006-01-01
Reversible variable length codes (RVLCs) have received much attention due to their excellent error resilient capabilities. In this paper, a novel construction algorithm for symmetrical RVLC is proposed which is independent of the Huffman code. The proposed algorithm's codeword assignment is only based on symbol occurrence probability. It has many advantages over symmetrical construction algorithms available for easy realization and better code performance. In addition, the proposed algorithm simplifies the codeword selection mechanism dramatically.
Directory of Open Access Journals (Sweden)
Eloisa Rosso dos Santos
2009-12-01
Full Text Available OBJETIVO: Correlacionar a classificação do RIFLE com a letalidade e tempo de internação na unidade de terapia intensiva e no hospital. MÉTODOS: Estudo de coorte prospectivo, observacional e longitudinal aprovado pelo Comitê de Ética da Instituição. Foram coletados os dados de todos os pacientes internados por mais de 24 horas na unidade de terapia intensiva do Hospital Universitário Polydoro Ernani de São Thiago da Universidade Federal de Santa Catarina de setembro de 2007 a março de 2008 e com seguimento até a alta ou óbito. Os pacientes foram divididos em dois grupos: com lesão renal aguda e sem lesão renal aguda. O grupo com lesão renal aguda foi classificado conforme o RIFLE e subdividido de acordo com a classe máxima alcançada: risco, injúria ou falência. Não foram incluídas as classes loss e end-stage no estudo. Analisou-se também APACHE II e SOFA. Utilizaram-se os testes t Student e Qui-Quadrado, principalmente. Um pOBJECTIVE: To correlate the RIFLE classification with mortality and length of stay both in the intensive care unit and hospital. METHODS: A prospective, observational, longitudinal cohort study, approved by the Institution's Ethics Committee. Data were collected for all patients staying longer than 24 hours in the intensive care unit of Hospital Universitário Polydoro Ernani de São Thiago - Universidade Federal de Santa Catarina from September 2007 to March 2008, followed-up either until discharge or death. Patients were divided in two groups: with or without acute kidney injury. The acute kidney injury group was additionally divided according to the RIFLE and sub-divided according to the maximal score in Risk, Injury of Failure. Loss and End-stage classes were not included in the study. APACHE II and SOFA were also evaluated. The t Student and Chi-Square tests were used. A P<0.05 was considered statistically significant. RESULTS: The sample included 129 patients, 52 (40.3% with acute kidney injury
FETAL FOOT LENGTH AND HAND LENGTH: RELATIONSHIP WITH CROWN RUMP LENGTH AND GESTATIONAL AGE
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Garima
2015-12-01
Full Text Available BACKGROUND Estimation of gestational age of fetus is of great medicolegal importance. Multiple parameters of the fetal anatomical measurements are in use. However, gestational age assessment may be difficult in fetus with anencephaly, hydrocephalus, short limb dysplasia, post mortem destruction or in mutilated case. Study of literature suggests that fetal foot has a characteristic pattern of normal growth and the fetal foot shows gradual increase in length relative to the length of the embryo and could be used to estimate gestational age. The purpose of the present study is to determine the accuracy in estimating gestational age using fetal foot and hand length by studying its relation with crown rump length in the foetuses of Manipuri origin. AIMS AND OBJECTIVES 1 To study the relationship between fetal crown rump length and fetal hand and foot length, thereby determining the accuracy in estimating gestational age by a cross-sectional study. MATERIALS AND METHODS A total of 100 formalin fixed fetuses of Manipuri origin, obtained from the Department of Obstetrics and Gynaecology, Regional Institute of Medical Sciences, Imphal, were included in the study, carried out in the Department of Anatomy, from February 2015 to July 2015. The parameters studied were crown rump length, foot length and hand length of fetuses. The data was analysed using SPSS software by regression analysis. Graphs were also plotted to determine pattern of growth and their correlation with crown rump length if any. RESULTS A total of 100 fetuses were studied, of which 43 were females and 57 were males. The mean foot length and hand length progressively increased with increase in crown rump length. Measurements were not significantly different in right or left side or among male and female fetuses. A statistically significant linear relationship was seen between foot length and crown rump length of the fetus (r=0.980, p<0.0001 and hand length and crown rump length of the fetus
Hu, T C
2002-01-01
Newly enlarged, updated second edition of a valuable text presents algorithms for shortest paths, maximum flows, dynamic programming and backtracking. Also discusses binary trees, heuristic and near optimums, matrix multiplication, and NP-complete problems. 153 black-and-white illus. 23 tables.Newly enlarged, updated second edition of a valuable, widely used text presents algorithms for shortest paths, maximum flows, dynamic programming and backtracking. Also discussed are binary trees, heuristic and near optimums, matrix multiplication, and NP-complete problems. New to this edition: Chapter 9
A Formula of Average Path Length for Unweighted Networks
Institute of Scientific and Technical Information of China (English)
LIU Chun-Ping; LIU Yu-Rong; HE Da-Ren; ZHU Lu-Jin
2008-01-01
In this paper, based on the adjacency matrix of the network and its powers, the formulas are derived for the shortest path and the average path length, and an effective algorithm is presented. Furthermore, an example is provided to demonstrate the proposed method.
Faster Algorithms for Computing Longest Common Increasing Subsequences
DEFF Research Database (Denmark)
Kutz, Martin; Brodal, Gerth Stølting; Kaligosi, Kanela
2011-01-01
We present algorithms for finding a longest common increasing subsequence of two or more input sequences. For two sequences of lengths n and m, where m⩾n, we present an algorithm with an output-dependent expected running time of and O(m) space, where ℓ is the length of an LCIS, σ is the size of t...
IMPEDANCE OF FINITE LENGTH RESISTOR
Energy Technology Data Exchange (ETDEWEB)
KRINSKY, S.; PODOBEDOV, B.; GLUCKSTERN, R.L.
2005-05-15
We determine the impedance of a cylindrical metal tube (resistor) of radius a, length g, and conductivity {sigma}, attached at each end to perfect conductors of semi-infinite length. Our main interest is in the asymptotic behavior of the impedance at high frequency, k >> 1/a. In the equilibrium regime, , the impedance per unit length is accurately described by the well-known result for an infinite length tube with conductivity {sigma}. In the transient regime, ka{sup 2} >> g, we derive analytic expressions for the impedance and wakefield.
Polyketide chain length control by chain length factor.
Tang, Yi; Tsai, Shiou-Chuan; Khosla, Chaitan
2003-10-22
Bacterial aromatic polyketides are pharmacologically important natural products. A critical parameter that dictates product structure is the carbon chain length of the polyketide backbone. Systematic manipulation of polyketide chain length represents a major unmet challenge in natural product biosynthesis. Polyketide chain elongation is catalyzed by a heterodimeric ketosynthase. In contrast to homodimeric ketosynthases found in fatty acid synthases, the active site cysteine is absent from the one subunit of this heterodimer. The precise role of this catalytically silent subunit has been debated over the past decade. We demonstrate here that this subunit is the primary determinant of polyketide chain length, thereby validating its designation as chain length factor. Using structure-based mutagenesis, we identified key residues in the chain length factor that could be manipulated to convert an octaketide synthase into a decaketide synthase and vice versa. These results should lead to novel strategies for the engineered biosynthesis of hitherto unidentified polyketide scaffolds.
Curve Length Estimation using Vertix Chain Code Curve Length Estimation
Directory of Open Access Journals (Sweden)
Habibollah Haron
2010-09-01
Full Text Available Most of the applications in image analysis are based on Freeman chain code. In this paper, for the first time, vertex chain code (VCC proposed by Bribiesca is applied to improve length estimation of the 2D digitized curve. The chain code has some preferences such as stable in shifting, turning, mirroring movement of image and has normalized starting point. Due to the variety of length estimator methods, we focused on the three specific techniques. First, the way Bribiesca proposed which is based on counting links between vertices; second, based on maximum length digital straight segments (DSSs and lastly local metrics. The results of these length estimators with the real perimeter are compared. Results thus obtained exhibits thatlength estimation using VCC is nearest to the actual length.
Directory of Open Access Journals (Sweden)
Anna Bourmistrova
2011-02-01
Full Text Available The autodriver algorithm is an intelligent method to eliminate the need of steering by a driver on a well-defined road. The proposed method performs best on a four-wheel steering (4WS vehicle, though it is also applicable to two-wheel-steering (TWS vehicles. The algorithm is based on coinciding the actual vehicle center of rotation and road center of curvature, by adjusting the kinematic center of rotation. The road center of curvature is assumed prior information for a given road, while the dynamic center of rotation is the output of dynamic equations of motion of the vehicle using steering angle and velocity measurements as inputs. We use kinematic condition of steering to set the steering angles in such a way that the kinematic center of rotation of the vehicle sits at a desired point. At low speeds the ideal and actual paths of the vehicle are very close. With increase of forward speed the road and tire characteristics, along with the motion dynamics of the vehicle cause the vehicle to turn about time-varying points. By adjusting the steering angles, our algorithm controls the dynamic turning center of the vehicle so that it coincides with the road curvature center, hence keeping the vehicle on a given road autonomously. The position and orientation errors are used as feedback signals in a closed loop control to adjust the steering angles. The application of the presented autodriver algorithm demonstrates reliable performance under different driving conditions.
面向自动组卷问题的改进类电磁算法%Improved electromagnetism-like mechanism algorithm for automatic test paper problem
Institute of Scientific and Technical Information of China (English)
杨世达; 金敏; 梅磊
2011-01-01
类电磁算法(EM)中局部搜索是按一定步长进行线性搜索,在这个范围内寻找个体在某一维上的最优值.由于步长的限定,求得的该维上最优值可能远离实际的最优值.采用遗传算法(GA)中选择因子和交叉因子可以很好地解决这一问题.在组卷系统中,通过基于遗传算法改进的类电磁算法(Based Genetic Electromagnetism-like Mechanism Algorithm,GEM)与GA算法以及采用线性局部搜索的EM算法实验的比较,证明该算法有更高的组卷效率.%Local search of Electromagnetism-like Mechanism algorithm (EM) is linear searched by a certain step length, which finds the optimal value in a particular dimension in this individual.As the limit of step length,the optimal value may be far from the actual value of a particular dimension.To solve this problem, the select and crossover factor of Genetic Algorithm (GA) is the good way.In the automatic test paper system, compared with the Based Genetic Electromagnetism-like Mechanism Algorithm(GEM),GA and the EM of linear search in experiments show that the GEM has higher efficiency test paper.
Impedance of Finite Length Resistor
Krinsky, Samuel; Podobedov, Boris
2005-01-01
We determine the impedance of a cylindrical metal tube (resistor) of radius a and length g, attached at each end to perfect conductors of semi-infinite length. Our main interest is in the behavior of the impedance at high frequency (k>>1/a). In the equilibrium regime, ka2
Line Lengths and Starch Scores.
Moriarty, Sandra E.
1986-01-01
Investigates readability of different line lengths in advertising body copy, hypothesizing a normal curve with lower scores for shorter and longer lines, and scores above the mean for lines in the middle of the distribution. Finds support for lower scores for short lines and some evidence of two optimum line lengths rather than one. (SKC)
Synthesis, Crystal Structure and Luminescent Property of Cd (II Complex with <em>N-Benzenesulphonyl-L>-leucine
Directory of Open Access Journals (Sweden)
Xishi Tai
2012-09-01
Full Text Available A new trinuclear Cd (II complex [Cd_{3}(L_{6}(2,2-bipyridine_{3}] [L =<em> Nem>-phenylsulfonyl-L>-leucinato] has been synthesized and characterized by elemental analysis, IR and X-ray single crystal diffraction analysis. The results show that the complex belongs to the orthorhombic, space group<em> Pem>2_{1}2_{1}2_{1} with<em> aem> = 16.877(3 Å, <em>b> em>= 22.875(5 Å, <em>c em>= 29.495(6 Å, <em>α> em>= <em>β em>= <em>γ em>= 90°, <em>V> em>= 11387(4 Å^{3}, <em>Z> em>= 4, <em>D_{c}>= 1.416 μg·m^{−3}, <em>μ em>= 0.737 mm^{−1}, <em>F> em>(000 = 4992, and final <em>R>_{1} = 0.0390, <em>ωR>_{2} = 0.0989. The complex comprises two seven-coordinated Cd (II atoms, with a N_{2}O_{5} distorted pengonal bipyramidal coordination environment and a six-coordinated Cd (II atom, with a N_{2}O_{4} distorted octahedral coordination environment. The molecules form one dimensional chain structure by the interaction of bridged carboxylato groups, hydrogen bonds and p-p interaction of 2,2-bipyridine. The luminescent properties of the Cd (II complex and <em>N-Benzenesulphonyl-L>-leucine in solid and in CH_{3}OH solution also have been investigated.
Gestation length in farmed reindeer.
Shipka, M P; Rowell, J E
2010-01-01
Reindeer (Rangifer tarandus tarundus) are the only cervids indigenous to the arctic environment. In Alaska, reindeer are a recognized agricultural species and an economic mainstay for many native populations. Traditionally raised in extensive free-ranging systems, a recent trend toward intensive farming requires a more in-depth knowledge of reproductive management. Reported gestation length in reindeer varies, ranging from 198 to 229 d in studies performed at the University of Alaska Fairbanks. A switchback study that manipulated only breeding date demonstrated a mean increase in gestation length of 8.5 d among females bred early in the season. The negative correlation between conception date and gestation length is consistent with reindeer research at other locations and reports of variable gestation length in a growing number of domestic and non-domestic species. This paper reviews the phenomenon in reindeer and discusses some of the factors known to affect gestation length as well as possible areas for future research.
An improved affine projection algorithm for active noise cancellation
Zhang, Congyan; Wang, Mingjiang; Han, Yufei; Sun, Yunzhuo
2017-08-01
Affine projection algorithm is a signal reuse algorithm, and it has a good convergence rate compared to other traditional adaptive filtering algorithm. There are two factors that affect the performance of the algorithm, which are step factor and the projection length. In the paper, we propose a new variable step size affine projection algorithm (VSS-APA). It dynamically changes the step size according to certain rules, so that it can get smaller steady-state error and faster convergence speed. Simulation results can prove that its performance is superior to the traditional affine projection algorithm and in the active noise control (ANC) applications, the new algorithm can get very good results.
Comparison of fast discrete wavelet transform algorithms
Institute of Scientific and Technical Information of China (English)
MENG Shu-ping; TIAN Feng-chun; XU Xin
2005-01-01
This paper presents an analysis on and experimental comparison of several typical fast algorithms for discrete wavelet transform (DWT) and their implementation in image compression, particularly the Mallat algorithm, FFT-based algorithm, Short-length based algorithm and Lifting algorithm. The principles, structures and computational complexity of these algorithms are explored in details respectively. The results of the experiments for comparison are consistent to those simulated by MATLAB. It is found that there are limitations in the implementation of DWT. Some algorithms are workable only for special wavelet transform, lacking in generality. Above all, the speed of wavelet transform, as the governing element to the speed of image processing, is in fact the retarding factor for real-time image processing.
Chain-length dependent <em>para>-phenyelene film- and needle-growth on dielectrics
DEFF Research Database (Denmark)
Balzer, Frank; Rubahn, Horst-Günter
2004-01-01
Surface unit cells of vacuum grown ultrathin films of blue-light emitting para-phenylene oligomers on alkali halides and on muscovite mica have been determined using low energy electron diffraction. Both, films from upright and from laying molecules are grown on alkali halide (1 0 0) and mica (0 ...... by the orientation of mica surface dipoles. Structural information from diffraction experiments is complemented by morphological information using fluorescence- and atomic force microscopy as well as UV/vis absorption spectroscopy....
<em>DCAF4em>, a novel gene associated with leucocyte telomere length
DEFF Research Database (Denmark)
Mangino, Massimo; Christiansen, Lene; Stone, Rivka
2015-01-01
is increased with ultraviolet radiation (UVR). RESULTS: Genome-wide association (GWA) meta-analysis and de novo genotyping of 20 022 individuals revealed a novel association (p=6.4×10(-10)) between LTL and rs2535913, which lies within DCAF4. Notably, eQTL analysis showed that rs2535913 is associated...... was to establish whether DCAF4 (DDB1 and CUL4-associated factor 4) is associated with LTL. In addition, using ingenuity pathway analysis (IPA), we examined whether LTL-associated genes in the general population might partially explain the inherently longer LTL in patients with sporadic melanoma, the risk for which...... with decline in DCAF4 expressions in both lymphoblastoid cells and sun-exposed skin (p=4.1×10(-3) and 2×10(-3), respectively). Moreover, IPA revealed that LTL-associated genes, derived from GWA meta-analysis (N=9190), are over-represented among genes engaged in melanoma pathways. Meeting increasingly stringent...
DEFF Research Database (Denmark)
Markham, Annette
layered set of accounts to help build our understanding of how individuals relate to their devices, search systems, and social network sites. This work extends critical analyses of the power of algorithms in implicating the social self by offering narrative accounts from multiple perspectives. It also......This paper takes an actor network theory approach to explore some of the ways that algorithms co-construct identity and relational meaning in contemporary use of social media. Based on intensive interviews with participants as well as activity logging and data tracking, the author presents a richly...... contributes an innovative method for blending actor network theory with symbolic interaction to grapple with the complexity of everyday sensemaking practices within networked global information flows....
A fast DFT algorithm using complex integer transforms
Reed, I. S.; Truong, T. K.
1978-01-01
Winograd's algorithm for computing the discrete Fourier transform is extended considerably for certain large transform lengths. This is accomplished by performing the cyclic convolution, required by Winograd's method, by a fast transform over certain complex integer fields. This algorithm requires fewer multiplications than either the standard fast Fourier transform or Winograd's more conventional algorithms.
A global heuristically search algorithm for DNA encoding
Institute of Scientific and Technical Information of China (English)
Zhang Kai; Pan Linqiang; Xu Jin
2007-01-01
A new efficient algorithm is developed to design DNA words with equal length for DNA computing. The algorithm uses a global heuristic optimizing search approach and converts constraints to a carry number to accelerate the convergence, which can generate a DNA words set satisfying some thermodynamic and combinatorial constraints. Based on the algorithm, a software for DNA words design is developed.
Hardware modules of the RSA algorithm
Directory of Open Access Journals (Sweden)
Škobić Velibor
2014-01-01
Full Text Available This paper describes basic principles of data protection using the RSA algorithm, as well as algorithms for its calculation. The RSA algorithm is implemented on FPGA integrated circuit EP4CE115F29C7, family Cyclone IV, Altera. Four modules of Montgomery algorithm are designed using VHDL. Synthesis and simulation are done using Quartus II software and ModelSim. The modules are analyzed for different key lengths (16 to 1024 in terms of the number of logic elements, the maximum frequency and speed.
Minimum length-maximum velocity
Panes, Boris
2012-03-01
We study a framework where the hypothesis of a minimum length in space-time is complemented with the notion of reference frame invariance. It turns out natural to interpret the action of the obtained reference frame transformations in the context of doubly special relativity. As a consequence of this formalism we find interesting connections between the minimum length properties and the modified velocity-energy relation for ultra-relativistic particles. For example, we can predict the ratio between the minimum lengths in space and time using the results from OPERA on superluminal neutrinos.
Models and Algorithms for Tracking Target with Coordinated Turn Motion
Directory of Open Access Journals (Sweden)
Xianghui Yuan
2014-01-01
Full Text Available Tracking target with coordinated turn (CT motion is highly dependent on the models and algorithms. First, the widely used models are compared in this paper—coordinated turn (CT model with known turn rate, augmented coordinated turn (ACT model with Cartesian velocity, ACT model with polar velocity, CT model using a kinematic constraint, and maneuver centered circular motion model. Then, in the single model tracking framework, the tracking algorithms for the last four models are compared and the suggestions on the choice of models for different practical target tracking problems are given. Finally, in the multiple models (MM framework, the algorithm based on expectation maximization (EM algorithm is derived, including both the batch form and the recursive form. Compared with the widely used interacting multiple model (IMM algorithm, the EM algorithm shows its effectiveness.
Metal detector depth estimation algorithms
Marble, Jay; McMichael, Ian
2009-05-01
This paper looks at depth estimation techniques using electromagnetic induction (EMI) metal detectors. Four algorithms are considered. The first utilizes a vertical gradient sensor configuration. The second is a dual frequency approach. The third makes use of dipole and quadrapole receiver configurations. The fourth looks at coils of different sizes. Each algorithm is described along with its associated sensor. Two figures of merit ultimately define algorithm/sensor performance. The first is the depth of penetration obtainable. (That is, the maximum detection depth obtainable.) This describes the performance of the method to achieve detection of deep targets. The second is the achievable statistical depth resolution. This resolution describes the precision with which depth can be estimated. In this paper depth of penetration and statistical depth resolution are qualitatively determined for each sensor/algorithm. A scientific method is used to make these assessments. A field test was conducted using 2 lanes with emplaced UXO. The first lane contains 155 shells at increasing depths from 0" to 48". The second is more realistic containing objects of varying size. The first lane is used for algorithm training purposes, while the second is used for testing. The metal detectors used in this study are the: Geonics EM61, Geophex GEM5, Minelab STMR II, and the Vallon VMV16.
<em>α>-Glucosidase Inhibitory Constituents from <em>Acanthopanax senticosusem> Harm Leaves
Directory of Open Access Journals (Sweden)
Hai-Xue Kuang
2012-05-01
Full Text Available A new triterpene glycoside, 3-<em>O-[(α>-L-rhamnopyranosyl(1→2]-[<em>β>-D-glucuronopyranosyl-6-<em>O>-methyl ester]-olean-12-ene-28-olic acid (1 and a new indole alkaloid, 5-methoxy-2-oxoindolin-3-acetic acid methyl ester (5 were isolated from the leaves of <em>Acanthopanax senticosusem> Harms along with six known compounds. The structures of the new compounds were determined by means of 2D-NMR experiments and chemical methods. All the isolated compounds were evaluated for their glycosidase inhibition activities and compound 6 showed significant <em>α>-glucosidase inhibition activity.
Pairing versus quarteting coherence length
Delion, Doru S
2015-01-01
We systematically analyse the coherence length in even-even nuclei. The pairing coherence length in the spin-singlet channel for the effective density dependent delta (DDD) and Gaussian interaction is estimated. We consider in our calculations bound states as well as narrow resonances. It turns out that the pairing gaps given by the DDD interaction are similar to those of the Gaussian potential if one renormalizes the radial width to the nuclear radius. The correlations induced by the pairing interaction have in all considered cases a long range character inside the nucleus and decrease towards the surface. The mean coherence length is larger than the geometrical radius for light nuclei and approaches this value for heavy nuclei. The effect of the temperature and states in continuum is investigated. Strong shell effects are evidenced, especially for protons. We generalize this concept to quartets by considering similar relations, but between proton and neutron pairs. The quartet coherence length has a similar...
Energy Technology Data Exchange (ETDEWEB)
Gewehr, Diego N.; Vargas, Ricardo B.; Melo, Eduardo D. de; Paschoareli Junior, Dionizio [Universidade Estadual Paulista (DEE/UNESP), Ilha Solteira, SP (Brazil). Dept. de Engenharia Eletrica. Grupo de Pesquisa em Fontes Alternativas e Aproveitamento de Energia
2008-07-01
This paper presents a methodology for electric power sources location in isolated direct current micro grids, using genetic algorithm. In this work, photovoltaic panels are considered, although the methodology can be extended for any kind of DC sources. A computational tool is developed using the Matlab simulator, to obtain the best dc system configuration for reduction of panels quantity and costs, and to improve the system performance. (author)
Length Invisibilization of Tachyonic Neutrinos
Estakhr, Ahmad Reza
2016-09-01
Faster than the speed of light particle such as tachyonic neutrino due to its superluminal nature disapper and is undetectable. L = iΩ-1Lo where, i =√{ - 1 } is imaginary Number, Ω = 1 /√{βs2 - 1 } is Estakhr's Omega factor, L is the Superluminal Length, Lo is the proper length, βs =Vs / c > 1 is superluminal speed parameter, Vs is Superluminal velocity and c is speed of light.
Energy Technology Data Exchange (ETDEWEB)
Malthez, Anna Luiza M.C.; Button, Vera L. da S.N. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Faculdade de Engenharia Eletrica e de Computacao. Dept. de Engenharia Biomedica; Rocha, Jose R. de O. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Centro de Engenharia Biomedica
2009-07-01
In this work a bibliographic review was made about the GEANT4 applicability in radiotherapy, and also a study of electrons transport algorithm in order to establish the key points for future works with GEANT4. In papers already published, the GEANT4 version 4.6.1 was considered appropriated for photons simulations in applications of clinic significance in radiotherapy (accuracy {approx} 2%), however to electrons was checked that versions older than 8.3 present problems related to electrons transport algorithm, as size step artifact. The GEANT4 algorithm revision, version 8.3, resulted in substantial improvements of some values calculated in simulations, especially the loss energy per step and the boundary vicinity simulation of electrons, beyond better results stability, compared to versions 8.2. We concluded that electrons transport parameters within the following ranges: dRoverRange<0.3, RangeFactor=0.02, GeomFactor=3 and skin=1 is possible to get results with 1% accuracy to cavities simulations, although occur differences between simulated and theoretical doses, indicating that others parameters and the dose shift should be better evaluated. (author)
Efficient Algorithms for Bayesian Network Parameter Learning from Incomplete Data
2015-07-01
Efficient Algorithms for Bayesian Network Parameter Learning from Incomplete Data Guy Van den Broeck∗ and Karthika Mohan∗ and Arthur Choi and Adnan...We propose a family of efficient algorithms for learning the parameters of a Bayesian network from incomplete data. Our approach is based on recent...algorithms like EM (which require inference). 1 INTRODUCTION When learning the parameters of a Bayesian network from data with missing values, the
Application of Fuzzy Logic to EMS-type Magnetically Levitated Railway Vehicle
Kusagawa, Shinichi; Baba, Jumpei; Shutoh, Katsuhiko; Masada, Eisuke
A type of the magnetically levitated railway system with the electro-magnetic suspension system (EMS), which is named HSST system, will be put into revenue service as an urban transport in Nagoya, Japan at the beginning of April 2005. To extend its operational velocity higher than 200km/h for applications in other cities, the design of its EMS system is reexamined for improvement of riding comfort and performances of a train. In order to achieve these objectives, the multipurpose optimization on the basis of the genetic algorithm is applied for the design of EMS-type magnetically levitated vehicle, control parameters of which are optimized both to follow the rail exactly in high-speed and to provide enough riding comfort to passengers. However, the ability to follow sharp irregularities of the rail and to cope with high frequency noises in the gap length control system should be coordinated with riding comfort. The fuzzy logic is introduced into the dynamic control loop and verified to solve the problem. Far better coordination is obtained between the vehicle performances and riding comfort of passengers in high-speed against such various rail conditions. The levitation control with fuzzy logic is shown to be useful for the critical design problem as the high-speed maglev railways.
Casanova, Henri; Robert, Yves
2008-01-01
""…The authors of the present book, who have extensive credentials in both research and instruction in the area of parallelism, present a sound, principled treatment of parallel algorithms. … This book is very well written and extremely well designed from an instructional point of view. … The authors have created an instructive and fascinating text. The book will serve researchers as well as instructors who need a solid, readable text for a course on parallelism in computing. Indeed, for anyone who wants an understandable text from which to acquire a current, rigorous, and broad vi
DEFF Research Database (Denmark)
Gustavson, Fred G.; Reid, John K.; Wasniewski, Jerzy
2007-01-01
variables, and the speed is usually better than that of the LAPACK algorithm that uses full storage (n2 variables). Included are subroutines for rearranging a matrix whose upper or lower-triangular part is packed by columns to this format and for the inverse rearrangement. Also included is a kernel......We present subroutines for the Cholesky factorization of a positive-definite symmetric matrix and for solving corresponding sets of linear equations. They exploit cache memory by using the block hybrid format proposed by the authors in a companion article. The matrix is packed into n(n + 1)/2 real...
On Line Segment Length and Mapping 4-regular Grid Structures in Network Infrastructures
DEFF Research Database (Denmark)
Riaz, Muhammad Tahir; Nielsen, Rasmus Hjorth; Pedersen, Jens Myrup;
2006-01-01
The paper focuses on mapping the road network into 4-regular grid structures. A mapping algorithm is proposed. To model the road network GIS data have been used. The Geographic Information System (GIS) data for the road network are composed with different size of line segment lengths....... The manipulation of the line segment length for mapping is analyzed. The algorithms and simulation results are given in the paper....
Constrained length minimum inductance gradient coil design.
Chronik, B A; Rutt, B K
1998-02-01
A gradient coil design algorithm capable of controlling the position of the homogeneous region of interest (ROI) with respect to the current-carrying wires is required for many advanced imaging and spectroscopy applications. A modified minimum inductance target field method that allows the placement of a set of constraints on the final current density is presented. This constrained current minimum inductance method is derived in the context of previous target field methods. Complete details are shown and all equations required for implementation of the algorithm are given. The method has been implemented on computer and applied to the design of both a 1:1 aspect ratio (length:diameter) central ROI and a 2:1 aspect ratio edge ROI gradient coil. The 1:1 design demonstrates that a general analytic method can be used to easily obtain very short gradient coil designs for use with specialized magnet systems. The edge gradient design demonstrates that designs that allow imaging of the neck region with a head sized gradient coil can be obtained, as well as other applications requiring edge-of-cylinder regions of uniformity.
A Novel Algorithm for Finding Interspersed Repeat Regions
Institute of Scientific and Technical Information of China (English)
Dongdong Li; Zhengzhi Wang; Qingshan Ni
2004-01-01
The analysis of repeats in the DNA sequences is an important subject in bioinformatics. In this paper, we propose a novel projection-assemble algorithm to find unknown interspersed repeats in DNA sequences. The algorithm employs random projection algorithm to obtain a candidate fragment set, and exhaustive search algorithm to search each pair of fragments from the candidate fragment set to find potential linkage, and then assemble them together. The complexity of our projection-assemble algorithm is nearly linear to the length of the genome sequence, and its memory usage is limited by the hardware. We tested our algorithm with both simulated data and real biology data, and the results show that our projection-assemble algorithm is efficient. By means of this algorithm, we found an un-labeled repeat region that occurs five times in Escherichia coli genome, with its length more than 5,000 bp, and a mismatch probability less than 4%.
BIT LENGTH REPLACEMENT STEGANOGRAPHY BASED ON DCT COEFFICIENTS
Directory of Open Access Journals (Sweden)
K B Shiva Kumar
2010-08-01
Full Text Available Steganography is a means of establishing secret communication through public channel in an artistic manner. In this paper, we propose Bit Length Replacement Steganography Based on DCT Coefficients (BLSDCT . The cover image is segmented into 8*8 blocks and DCT is applied on each block. The numbers of payload MSB bits are embedded into DCT coefficients of the cover image based on the values of DCT oefficients. It is observed that the proposed algorithm has better PSNR, Security and capacity compared to the existing algorithm.
Fu, J C; Chen, C C; Chai, J W; Wong, S T C; Li, I C
2010-06-01
We propose an automatic hybrid image segmentation model that integrates the statistical expectation maximization (EM) model and the spatial pulse coupled neural network (PCNN) for brain magnetic resonance imaging (MRI) segmentation. In addition, an adaptive mechanism is developed to fine tune the PCNN parameters. The EM model serves two functions: evaluation of the PCNN image segmentation and adaptive adjustment of the PCNN parameters for optimal segmentation. To evaluate the performance of the adaptive EM-PCNN, we use it to segment MR brain image into gray matter (GM), white matter (WM) and cerebrospinal fluid (CSF). The performance of the adaptive EM-PCNN is compared with that of the non-adaptive EM-PCNN, EM, and Bias Corrected Fuzzy C-Means (BCFCM) algorithms. The result is four sets of boundaries for the GM and the brain parenchyma (GM+WM), the two regions of most interest in medical research and clinical applications. Each set of boundaries is compared with the golden standard to evaluate the segmentation performance. The adaptive EM-PCNN significantly outperforms the non-adaptive EM-PCNN, EM, and BCFCM algorithms in gray mater segmentation. In brain parenchyma segmentation, the adaptive EM-PCNN significantly outperforms the BCFCM only. However, the adaptive EM-PCNN is better than the non-adaptive EM-PCNN and EM on average. We conclude that of the three approaches, the adaptive EM-PCNN yields the best results for gray matter and brain parenchyma segmentation.
An algorithm for link restoration of wavelength routing optical networks
DEFF Research Database (Denmark)
Limal, Emmanuel; Stubkjær, Kristian
1999-01-01
We present an algorithm for restoration of single link failure in wavelength routing multihop optical networks. The algorithm is based on an innovative study of networks using graph theory. It has the following original features: it (i) assigns working and spare channels simultaneously, (ii...... low complexity is studied in detail and compared to the complexity of a classical path assignment algorithm. Finally, we explain how to use the algorithm to control the restoration path lengths....
Directory of Open Access Journals (Sweden)
safieh Akbary rad
2009-11-01
Full Text Available Abstract Three species of the genus <em>Rattus> Fisher, 1803 have been reported from Iran: the brown rat (<em>R. norvegicusem>, the black rat (<em>R. rattusem> and the Himalayan rat (<em>R. pyctorisem>. The first two were introduced, whilst <em>R. pyctorisem> is native and lives in mountainous regions from Pakistan to north-eastern Iran. In this study, the mitochondrial DNA from twenty six rats were analysed using a PCR-RFLP (Polymerase Chain Reaction - Restriction Fragments Length Polymorphism method to investigate inter-specific variation. Part of the 16S rRNA and cytochrome b genes were amplified and digested with three restriction enzymes: AluI, MboI and HinfI. Restriction fragments resulted in four different haplotypes and allowed to distinguish the three <em>Rattus> species. Our results suggest that the Himalayan rats are more closely related to <em>R. rattusem> than to <em>R. norvegicusem> and provide the basics for further phylogenetic studies. Riassunto Identificazione di tre specie iraniane del genere <em>Rattus> (Rodentia, Muridae tramite PCR-RFLP su DNA mitocondriale. Tre specie del genere <em>Rattus> risultano diffuse in Iran: il surmolotto (<em>R. norvegicusem>, il ratto nero (<em>R. rattusem> e il ratto himalayano (<em>R. pyctorisem>. Le prime due specie sono state introdotte, mentre <em>R. pyctorisem> è presente nelle aree montane che si sviluppano dal Pakistan all’Iran nordorientale. In questo studio, il DNA mitocondriale di 26 individui è stato analizzato tramite PCR-RFLP per evidenziare variazioni inter-specifiche. Parte dei geni del rRNA 16S e del citocromo b è stata amplificata e quindi sottoposta a digestione tramite tre diversi enzimi: AluI, MboI e HinfI. I frammenti di restrizione hanno permesso di individuare quattro aplotipi mitocondriali e di distinguere le tre specie. I risultati ottenuti suggeriscono che il ratto
SHORTEST PATH ARC LENGTH NETWORK USING TRIANGULAR INTUITIONISTIC FUZZY NUMBER
Directory of Open Access Journals (Sweden)
A.D.CHANDRASEKARAN
2016-04-01
Full Text Available In this paper, an intuitionistic fuzzy shortest path is presented to find the optimal path in a network which a fuzzy number, instead of a positive integer is assigned to each arc length. The algorithm is based on the idea that firstly from all the shortest paths from source to destination, an arc with shortest length is computed and then the Euclidean distance is computed for all the paths with the arc of minimum distance. Finally an illustrative numerical example is given to express the proposed work.
Energy Technology Data Exchange (ETDEWEB)
Vieira, Jose Wilson; Leal Neto, Viriato; Lima Filho, Jose de Melo, E-mail: jose.wilson59@uol.com.br [Instituto Federal de Educacao Ciencia e Tecnologia de Pernambuco (IFPE), Recife, PE (Brazil); Lima, Fernando Roberto de Andrade [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)
2013-07-01
This paper presents as algorithm of a planar and isotropic radioactive source and by rotating the probability density function (PDF) Gaussian standard subjected to a translatory method which displaces its maximum throughout its field changes its intensity and makes the dispersion around the mean right asymmetric. The algorithm was used to generate samples of photons emerging from a plane and reach a semicircle involving a phantom voxels. The PDF describing this problem is already known, but the generating function of random numbers (FRN) associated with it can not be deduced by direct MC techniques. This is a significant problem because it can be adjusted to simulations involving natural terrestrial radiation or accidents in medical establishments or industries where the radioactive material spreads in a plane. Some attempts to obtain a FRN for the PDF of the problem have already been implemented by the Research Group in Numerical Dosimetry (GND) from Recife-PE, Brazil, always using the technique rejection sampling MC. This article followed methodology of previous work, except on one point: The problem of the PDF was replaced by a normal PDF transferred. To perform dosimetric comparisons, we used two MCES: the MSTA (Mash standing, composed by the adult male voxel phantom in orthostatic position, MASH (male mesh), available from the Department of Nuclear Energy (DEN) of the Federal University of Pernambuco (UFPE), coupled to MC EGSnrc code and the GND planar source based on the rejection technique) and MSTA{sub N}T. The two MCES are similar in all but FRN used in planar source. The results presented and discussed in this paper establish the new algorithm for a planar source to be used by GND.
Persistence Length of Stable Microtubules
Hawkins, Taviare; Mirigian, Matthew; Yasar, M. Selcuk; Ross, Jennifer
2011-03-01
Microtubules are a vital component of the cytoskeleton. As the most rigid of the cytoskeleton filaments, they give shape and support to the cell. They are also essential for intracellular traffic by providing the roadways onto which organelles are transported, and they are required to reorganize during cellular division. To perform its function in the cell, the microtubule must be rigid yet dynamic. We are interested in how the mechanical properties of stable microtubules change over time. Some ``stable'' microtubules of the cell are recycled after days, such as in the axons of neurons or the cilia and flagella. We measured the persistence length of freely fluctuating taxol-stabilized microtubules over the span of a week and analyzed them via Fourier decomposition. As measured on a daily basis, the persistence length is independent of the contour length. Although measured over the span of the week, the accuracy of the measurement and the persistence length varies. We also studied how fluorescently-labeling the microtubule affects the persistence length and observed that a higher labeling ratio corresponded to greater flexibility. National Science Foundation Grant No: 0928540 to JLR.
Energy Technology Data Exchange (ETDEWEB)
Lapa, Celso M. Franklin; Pereira, Claudio M.N.A.; Mol, Antonio C. de Abreu [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil)
1999-07-01
This paper presents a solution based on genetic algorithm and probabilistic safety analysis that can be applied in the optimization of the preventive maintenance politic of nuclear power plant safety systems. The goal of this approach is to improve the average availability of the system through the optimization of the preventive maintenance scheduling politic. The auxiliary feed water system of a two loops pressurized water reactor is used as a sample case, in order to demonstrate the effectiveness of the proposed method. The results, when compared to those obtained by some standard maintenance politics, reveal quantitative gains and operational safety levels. (author)
Alsolami, Fawaz
2013-01-01
This paper is devoted to the study of algorithms for sequential optimization of approximate inhibitory rules relative to the length, coverage and number of misclassifications. Theses algorithms are based on extensions of dynamic programming approach. The results of experiments for decision tables from UCI Machine Learning Repository are discussed. © 2013 Springer-Verlag.
Three New Myrsinol Diterpenes from <em>Euphorbia proliferaem> and Their Neuroprotective Activities
Directory of Open Access Journals (Sweden)
Yuanqiang Guo
2012-08-01
Full Text Available Three new myrsinol diterpenes were isolated from the roots of<em> em>>Euphorbia proliferaem>. Their structures were elucidated as 2<em>α-O>-isobutyryl-3<em>β>,5<em>α>,7<em>β>,10,15<em>β-penta-O>-acetyl-14<em>α-O>-benzoyl-10,18-dihydromyrsinol (1, 2<em>α-O>-isobutyryl-3<em>β-O>-propion-yl-5<em>α>,7<em>β>,10,15<em>β-tetra-O>-acetyl-10,18-dihydromyrsinol (2, and 2<em>α>,14<em>α-di-O>-benzoyl-3<em>β>,5<em>α>,7<em>β>,10,15<em>β-penta-O>-acetyl-10,18-dihydromyrsinol (3 on the basis of spectroscopic data analyses (IR, ESI-MS, HR-ESI-MS, and 1D and 2D NMR. Their neuroprotective activities were evaluated and compounds 1 and 2 showed neuroprotective effects against MPP^{+}-induced neuronal cell death in SH-SY5Y cells.
Temperature-dependence of Threshold Current Density-Length Product in Metallization Lines: A Revisit
Saptono Duryat, Rahmat; Kim, Choong-Un
2016-04-01
One of the important phenomena in Electromigration (EM) is Blech Effect. The existence of Threshold Current Density-Length Product or EM Threshold has such fundamental and technological consequences in the design, manufacture, and testing of electronics. Temperature-dependence of Blech Product had been thermodynamically established and the real behavior of such interconnect materials have been extensively studied. The present paper reviewed the temperature-dependence of EM threshold in metallization lines of different materials and structure as found in relevant published articles. It is expected that the reader can see a big picture from the compiled data, which might be overlooked when it was examined in pieces.
IMF Length Scales and Predictability: The Two Length Scale Medium
Collier, Michael R.; Szabo, Adam; Slavin, James A.; Lepping, R. P.; Kokubun, S.
1999-01-01
We present preliminary results from a systematic study using simultaneous data from three spacecraft, Wind, IMP 8 (Interplanetary Monitoring Platform) and Geotail to examine interplanetary length scales and their implications on predictability for magnetic field parcels in the typical solar wind. Time periods were selected when the plane formed by the three spacecraft included the GSE (Ground Support Equipment) x-direction so that if the parcel fronts were strictly planar, the two adjacent spacecraft pairs would determine the same phase front angles. After correcting for the motion of the Earth relative to the interplanetary medium and deviations in the solar wind flow from radial, we used differences in the measured front angle between the two spacecraft pairs to determine structure radius of curvature. Results indicate that the typical radius of curvature for these IMF parcels is of the order of 100 R (Sub E). This implies that there are two important IMF (Interplanetary Magnetic Field) scale lengths relevant to predictability: (1) the well-established scale length over which correlations observed by two spacecraft decay along a given IMF parcel, of the order of a few tens of Earth radii and (2) the scale length over which two spacecraft are unlikely to even observe the same parcel because of its curvature, of the order of a hundred Earth radii.
Electrophysiological evaluation in myotonic dystrophy: correlation with CTG length expansion
Directory of Open Access Journals (Sweden)
Pfeilsticker Beatriz Helena Miranda
2001-01-01
Full Text Available In myotonic dystrophy (MD, disease severity has been correlated with expansion of CTG repeats in chromosome 19. The aims of this study were to evaluate efficacy of electromyography in the diagnosis of MD, access the frequency and the characteristics of peripheral involvement in the disease and to verify whether the CTG repeats correlated with the electrophysiological abnormalities. Twenty-five patients and six relatives at risk of carrying the MD gene were examined. Electrical myotonia (EM was scored. Sensory and motor conduction velocity (CV were studied in five nerves. Leukocyte DNA analysis was done in 26 subjects. Myopathy and myotonia were found in 27 cases. EM was most frequent in muscles of hand and in tibialis anterior. No significant correlation was found between EM scores and length of CTG expansions. EM scores correlated significantly with the degree of clinical myopathy, expressed by a muscular disability scale. Peripheral neuropathy was found in eight subjects and was not restricted to those who were diabetics.
CEBAF Upgrade Bunch Length Measurements
Energy Technology Data Exchange (ETDEWEB)
Ahmad, Mahmoud [Old Dominion Univ., Norfolk, VA (United States)
2016-05-01
Many accelerators use short electron bunches and measuring the bunch length is important for efficient operations. CEBAF needs a suitable bunch length because bunches that are too long will result in beam interruption to the halls due to excessive energy spread and beam loss. In this work, bunch length is measured by invasive and non-invasive techniques at different beam energies. Two new measurement techniques have been commissioned; a harmonic cavity showed good results compared to expectations from simulation, and a real time interferometer is commissioned and first checkouts were performed. Three other techniques were used for measurements and comparison purposes without modifying the old procedures. Two of them can be used when the beam is not compressed longitudinally while the other one, the synchrotron light monitor, can be used with compressed or uncompressed beam.
Keeping disease at arm's length
DEFF Research Database (Denmark)
Lassen, Aske Juul
2015-01-01
active ageing change everyday life with chronic disease, and how do older people combine an active life with a range of chronic diseases? The participants in the study use activities to keep their diseases at arm’s length, and this distancing of disease at the same time enables them to engage in social...... and physical activities at the activity centre. In this way, keeping disease at arm’s length is analysed as an ambiguous health strategy. The article shows the importance of looking into how active ageing is practised, as active ageing seems to work well in the everyday life of the older people by not giving...... emphasis to disease. The article is based on ethnographic fieldwork and uses vignettes of four participants to show how they each keep diseases at arm’s length....
Spreading lengths of Hermite polynomials
Sánchez-Moreno, P; Manzano, D; Yáñez, R; 10.1016/j.cam.2009.09.043
2009-01-01
The Renyi, Shannon and Fisher spreading lengths of the classical or hypergeometric orthogonal polynomials, which are quantifiers of their distribution all over the orthogonality interval, are defined and investigated. These information-theoretic measures of the associated Rakhmanov probability density, which are direct measures of the polynomial spreading in the sense of having the same units as the variable, share interesting properties: invariance under translations and reflections, linear scaling and vanishing in the limit that the variable tends towards a given definite value. The expressions of the Renyi and Fisher lengths for the Hermite polynomials are computed in terms of the polynomial degree. The combinatorial multivariable Bell polynomials, which are shown to characterize the finite power of an arbitrary polynomial, play a relevant role for the computation of these information-theoretic lengths. Indeed these polynomials allow us to design an error-free computing approach for the entropic moments (w...
Tap-length optimization of adaptive filters used in stereophonic acoustic echo cancellation
DEFF Research Database (Denmark)
Kar, Asutosh; Swamy, M.N.S.
2017-01-01
of acoustic echo paths. The tap-length optimization is applied to a single long adaptive filter with thousands of coefficients to decrease the total number of weights, which in turn reduces the computational load. To further increase the convergence rate, the proposed tap-length-optimization algorithm...
Continuous lengths of oxide superconductors
Kroeger, Donald M.; List, III, Frederick A.
2000-01-01
A layered oxide superconductor prepared by depositing a superconductor precursor powder on a continuous length of a first substrate ribbon. A continuous length of a second substrate ribbon is overlaid on the first substrate ribbon. Sufficient pressure is applied to form a bound layered superconductor precursor powder between the first substrate ribbon and the second substrate ribbon. The layered superconductor precursor is then heat treated to establish the oxide superconducting phase. The layered oxide superconductor has a smooth interface between the substrate and the oxide superconductor.
Overview of bunch length measurements.
Energy Technology Data Exchange (ETDEWEB)
Lumpkin, A. H.
1999-02-19
An overview of particle and photon beam bunch length measurements is presented in the context of free-electron laser (FEL) challenges. Particle-beam peak current is a critical factor in obtaining adequate FEL gain for both oscillators and self-amplified spontaneous emission (SASE) devices. Since measurement of charge is a standard measurement, the bunch length becomes the key issue for ultrashort bunches. Both time-domain and frequency-domain techniques are presented in the context of using electromagnetic radiation over eight orders of magnitude in wavelength. In addition, the measurement of microbunching in a micropulse is addressed.
A Dynamic Programming Approach To Length-Limited Huffman Coding
Golin, Mordecai
2008-01-01
The ``state-of-the-art'' in Length Limited Huffman Coding algorithms is the $\\Theta(ND)$-time, $\\Theta(N)$-space one of Hirschberg and Larmore, where $D\\le N$ is the length restriction on the code. This is a very clever, very problem specific, technique. In this note we show that there is a simple Dynamic-Programming (DP) method that solves the problem with the same time and space bounds. The fact that there was an $\\Theta(ND)$ time DP algorithm was previously known; it is a straightforward DP with the Monge property (which permits an order of magnitude speedup). It was not interesting, though, because it also required $\\Theta(ND)$ space. The main result of this paper is the technique developed for reducing the space. It is quite simple and applicable to many other problems modeled by DPs with the Monge property. We illustrate this with examples from web-proxy design and wireless mobile paging.
2010-01-01
In this work we have compared two indexing algorithms that have been used to index and retrieve Carnatic music songs. We have compared a modified algorithm of the Dual ternary indexing algorithm for music indexing and retrieval with the multi-key hashing indexing algorithm proposed by us. The modification in the dual ternary algorithm was essential to handle variable length query phrase and to accommodate features specific to Carnatic music. The dual ternary indexing algorithm is ...
Directory of Open Access Journals (Sweden)
Chad H. Stahl
2012-05-01
Full Text Available Satellite cell activity is necessary for postnatal skeletal muscle growth. Severe phosphate (PO_{4} deficiency can alter satellite cell activity, however the role of neonatal PO_{4} nutrition on satellite cell biology remains obscure. Twenty-one piglets (1 day of age, 1.8 ± 0.2 kg BW were pair-fed liquid diets that were either PO_{4} adequate (0.9% total P, supra-adequate (1.2% total P in PO_{4} requirement or deficient (0.7% total P in PO_{4} content for 12 days. Body weight was recorded daily and blood samples collected every 6 days. At day 12, pigs were orally dosed with BrdU and 12 h later, satellite cells were isolated. Satellite cells were also cultured <em>in vitroem> for 7 days to determine if PO_{4} nutrition alters their ability to proceed through their myogenic lineage. Dietary PO_{4} deficiency resulted in reduced (<em>P> < 0.05 sera PO_{4} and parathyroid hormone (PTH concentrations, while supra-adequate dietary PO_{4} improved (<em>P> < 0.05 feed conversion efficiency as compared to the PO_{4} adequate group. <em>In vivoem> satellite cell proliferation was reduced (<em>P> < 0.05 among the PO_{4} deficient pigs, and these cells had altered <em>in vitroem> expression of markers of myogenic progression. Further work to better understand early nutritional programming of satellite cells and the potential benefits of emphasizing early PO_{4} nutrition for future lean growth potential is warranted.
Length Normalization in XML Retrieval
Kamps, Jaap; Rijke, Maarten de; Sigurbjörnsson, Börkur
2005-01-01
The full paper appeared as: J. Kamps, M. de Rijke, and B. Sigurbj¨ornsson, “Length Normalization in XML Retrieval,” In: Proceedings 27th Annual International ACM SIGIR Conference (SIGIR 2004), pages 80-87, 2004.
Finite length Taylor Couette flow
Streett, C. L.; Hussaini, M. Y.
1987-01-01
Axisymmetric numerical solutions of the unsteady Navier-Stokes equations for flow between concentric rotating cylinders of finite length are obtained by a spectral collocation method. These representative results pertain to two-cell/one-cell exchange process, and are compared with recent experiments.
African Journals Online (AJOL)
Administrator
from which stomachs were extracted for the analysis of the food contents, using frequency of occurrence, numerical and ... both fish species showed strong correlation between the weight and length with correlation coefficient (r) and ..... Basic data on the assessment of Sphyraena ... review of methods and their application.
Persistence length of dendronized polymers
Mikhailov, I.V.; Darinskii, A.A.; Zhulina, E.B.; Borisov, O.V.; Leermakers, F.A.M.
2015-01-01
We present numerical results for the thermodynamic rigidity and induced persistence length of dendronized polymers with systematically varied topology of their grafts obtained by the Scheutjens-Fleer self-consistent field method. The results were compared to predictions of an analytical mean-fiel
Directory of Open Access Journals (Sweden)
J. Vierinen
2011-06-01
Full Text Available We present a novel approach for modulating radar transmissions in order to improve target range and Doppler estimation accuracy. This is achieved by using non-uniform baud lengths. With this method it is possible to increase sub-baud range-resolution of phase coded radar measurements while maintaining a narrow transmission bandwidth. We first derive target backscatter amplitude estimation error covariance matrix for arbitrary targets when estimating backscatter in amplitude domain. We define target optimality and discuss different search strategies that can be used to find well performing transmission envelopes. We give several simulated examples of the method showing that fractional baud-length coding results in smaller estimation errors than conventional uniform baud length transmission codes when estimating the target backscatter amplitude at sub-baud range resolution. We also demonstrate the method in practice by analyzing the range resolved power of a low-altitude meteor trail echo that was measured using a fractional baud-length experiment with the EISCAT UHF system.
Cavity length below chute aerators
Institute of Scientific and Technical Information of China (English)
2008-01-01
It is proved that air entrainment is one of the efficient measures dealing with cavi-tation control for the release works of hydropower projects. There are many factors to be considered in designing a chute aerator. One of the most important factors concerns the cavity length below the aerator,which has outstanding effects on air entrainment against cavitation damage. It is crucial to determine reasonable emergence angle for the calculation of the cavity length. In the present paper the overall effects of structural and hydraulic parameters on the emergence angle of the flow from the aerator were analyzed. Four improved expressions of the emer-gence angle with weight coefficient were investigated through experimental data of 68 points observed from 12 aerators of 6 hydropower projects,of both model and prototype,on the basis of error theory. A method to calculate the cavity length be-low aerators was suggested,which considers overall effects of the above men-tioned parameters. Comparison between the method in this paper and the other five methods of calculating the cavity length showed that the present method is much more reliable than the existing methods while the mean error of the method is less than others.
Cavity length below chute aerators
Institute of Scientific and Technical Information of China (English)
WU JianHua; RUAN ShiPing
2008-01-01
It is proved that air entrainment is one of the efficient measures dealing with cavitation control for the release works of hydropower projects. There are many factors to be considered in designing a chute aerator. One of the most important factors concerns the cavity length below the aerator, which has outstanding effects on air entrainment against cavitation damage. It is crucial to determine reasonable emergence angle for the calculation of the cavity length. In the present paper the overall effects of structural and hydraulic parameters on the emergence angle of the flow from the aerator were analyzed. Four improved expressions of the emergence angle with weight coefficient were investigated through experimental data of 68 points observed from 12 aerators of 6 hydropower projects, of both model and prototype, on the basis of error theory. A method to calculate the cavity length below aerators was suggested, which considers overall effects of the above mentioned parameters. Comparison between the method in this paper and the other five methods of calculating the cavity length showed that the present method is much more reliable than the existing methods while the mean error of the method is less than others.
Indian Academy of Sciences (India)
Manju Pruthi
2001-11-01
In this paper explicit expressions of + 1 idempotents in the ring $R = F_q[X]/\\langle X^{2^m}-1\\rangle$ are given. Cyclic codes of length 2 over the finite field , of odd characteristic, are defined in terms of their generator polynomials. The exact minimum distance and the dimension of the codes are obtained.
Audio re-sampling detection in audio forensics based on EM algorithm%基于期望最大化算法的音频取证中的篡改检测
Institute of Scientific and Technical Information of China (English)
姚秋明; 柴佩琪; 宣国荣; 杨志强; 施云庆
2006-01-01
音频取证中的插值检测是信号篡改检测的重要方面.因为信号的篡改经常伴随着重采样操作,而重采样后的插值信号会引入周期性信息.应用期望最大化(EM)算法能针对这种周期信息估计参数,从而检测出信号是否被篡改.为了使EM算法迭代效果更好,更适用于音频信号的插值检测问题,提出针对音频信号的特点,引入音频幅度直方图,排除短时静音和增加样本点数的方法.另外还提出了用频谱统计矩作为特征的方法,使统计分类稳定有效.最后通过音频取证中检测信号是否重采样的统计分类实验,表明整个检测流程能达到较高的准确率,并且在局部篡改实验中也同样有效.
Evolutionary Graph Drawing Algorithms
Institute of Scientific and Technical Information of China (English)
Huang Jing-wei; Wei Wen-fang
2003-01-01
In this paper, graph drawing algorithms based on genetic algorithms are designed for general undirected graphs and directed graphs. As being shown, graph drawing algorithms designed by genetic algorithms have the following advantages: the frames of the algorithms are unified, the method is simple, different algorithms may be attained by designing different objective functions, therefore enhance the reuse of the algorithms. Also, aesthetics or constrains may be added to satisfy different requirements.
Algorithmic entropy, thermodynamics, and game interpretation
Sakhnovich, Lev
2011-01-01
Basic relations for the mean length and algorithmic entropy are obtained by solving a new extremal problem. Using this extremal problem, they are obtained in a most simple and general way. The length and entropy are considered as two players of a new type of a game, in which we follow the scheme of our previous work on thermodynamic characteristics in quantum and classical approaches.
Energy Technology Data Exchange (ETDEWEB)
Fontana, W.
1990-12-13
In this paper complex adaptive systems are defined by a self- referential loop in which objects encode functions that act back on these objects. A model for this loop is presented. It uses a simple recursive formal language, derived from the lambda-calculus, to provide a semantics that maps character strings into functions that manipulate symbols on strings. The interaction between two functions, or algorithms, is defined naturally within the language through function composition, and results in the production of a new function. An iterated map acting on sets of functions and a corresponding graph representation are defined. Their properties are useful to discuss the behavior of a fixed size ensemble of randomly interacting functions. This function gas'', or Turning gas'', is studied under various conditions, and evolves cooperative interaction patterns of considerable intricacy. These patterns adapt under the influence of perturbations consisting in the addition of new random functions to the system. Different organizations emerge depending on the availability of self-replicators.
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Gabrilelle Tayar
2007-09-01
Full Text Available OBJETIVOS: Este estudo descritivo teve por objetivos elaborar um algoritmo para apoiar a decisão da enfermeira na seleção de coberturas segundo o tipo de lesão aberta em crianças e avaliar sua aplicabilidade, segundo a opinião de enfermeiras pediátricas. MÉTODOS: O algoritmo desenvolvido é composto por determinantes relativos à avaliação do tecido e estágio de cicatrização, limpeza da ferida e tipo de cobertura primária e secundária utilizado. RESULTADOS: Entre as 24 enfermeiras que participaram da avaliação do algoritmo, o tempo de formadas e de trabalho em pediatria apresentou mediana de dois anos; 87,5% eram pós-graduandas e 100% cuidavam de uma a quatro crianças com feridas abertas por mês. Quanto a avaliação do algoritmo, na maioria das variáveis verificadas, o instrumento foi considerado ótimo. CONCLUSÃO: Após a utilização do algoritmo proposto, 95,8% das enfermeiras consideraram um importante instrumento para aplicação na prática assistencial.OBJETIVOS: Este estudio descriptivo tenido por objetivos elaborar un algoritmo para apoyar la decisión de la enfermera en la selecion del cuidado en los tipos diferentes de heridas presentado por los niños y evaluar la pertinencia practica, a través de la aplicación de un instrumento de la investigación. MÉTODOS: El algoritmo desarrollado y compuesto para el determinante relativa la limpieza de la herida, la evaluación clinica de aprendiz de cicatrisacion y tipo de primero y secundario curativo el ellos se usen. RESULTADOS: Los 24 enfermeras que participaron en la evaluación del algoritmo ellas poseyeron el mediana de dos años de formación y trabajan en la pediatría; 87,5% eran postgraduadas y 100,0% tuvieron el cuidado en el período de trabajo, de uno a cuatro niños con las heridas abiertas un mes. Como la evaluación del algoritmo, en la mayoría de las variables verificadas, el instrumento fue considerado grande. CONCLUSION: 95,8% de las enfermeras
Constituents from <em>Vigna em>vexillata> and Their Anti-Inflammatory Activity
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Guo-Feng Chen
2012-08-01
Full Text Available The seeds of <em>Vigna em>genus are important food resources and there have already been many reports regarding their bioactivities. In our preliminary bioassay, the chloroform layer of methanol extracts of<em> V. vexillata em>demonstrated significant anti-inflammatory bioactivity. Therefore, the present research is aimed to purify and identify the anti-inflammatory principles of <em>V. vexillataem>. One new sterol (1 and two new isoflavones (2,3 were reported from the natural sources for the first time and their chemical structures were determined by the spectroscopic and mass spectrometric analyses. In addition, 37 known compounds were identified by comparison of their physical and spectroscopic data with those reported in the literature. Among the isolates, daidzein (23, abscisic acid (25, and quercetin (40 displayed the most significant inhibition of superoxide anion generation and elastase release.
Graph run-length matrices for histopathological image segmentation.
Tosun, Akif Burak; Gunduz-Demir, Cigdem
2011-03-01
The histopathological examination of tissue specimens is essential for cancer diagnosis and grading. However, this examination is subject to a considerable amount of observer variability as it mainly relies on visual interpretation of pathologists. To alleviate this problem, it is very important to develop computational quantitative tools, for which image segmentation constitutes the core step. In this paper, we introduce an effective and robust algorithm for the segmentation of histopathological tissue images. This algorithm incorporates the background knowledge of the tissue organization into segmentation. For this purpose, it quantifies spatial relations of cytological tissue components by constructing a graph and uses this graph to define new texture features for image segmentation. This new texture definition makes use of the idea of gray-level run-length matrices. However, it considers the runs of cytological components on a graph to form a matrix, instead of considering the runs of pixel intensities. Working with colon tissue images, our experiments demonstrate that the texture features extracted from "graph run-length matrices" lead to high segmentation accuracies, also providing a reasonable number of segmented regions. Compared with four other segmentation algorithms, the results show that the proposed algorithm is more effective in histopathological image segmentation.
Generating Moving Average Trading Rules on the Oil Futures Market with Genetic Algorithms
National Research Council Canada - National Science Library
Wang, Lijun; An, Haizhong; Xia, Xiaohua; Liu, Xiaojia; Sun, Xiaoqi; Huang, Xuan
2014-01-01
.... We defined individuals with different combinations of period lengths and calculation methods as moving average trading rules and used genetic algorithms to search for the suitable lengths of moving...
Variable length data formats. [in hardware-software engineering
Brakefield, J. C.; Quinn, M. J.
1978-01-01
The purpose of this paper is to discuss a number of variable length floating point and integer formats and to give the various advantages and disadvantages of their use. Often it is known in advance that a given integer will not exceed a certain magnitude or that a particular floating point number is accurate to only 'n' places of accuracy. Faced with this, it is good engineering to choose variable length floating point and integer formats which require the least amount of hardware or the minimum amount of software or which have some other dominant advantage. The formats discussed have the advantage that length change algorithms are invariant with respect to data types (unsigned, signed, floating point, integers, and complex numbers). The STARAN associative array processor, which uses a completely variable fixed point and floating point formats, is described.
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Josef Jampilek
2012-08-01
Full Text Available A series of twenty-five novel salicylanilide <em>N>-alkylcarbamates were investigated as potential acetylcholinesterase inhibitors. The compounds were tested for their ability to inhibit acetylcholinesterase (AChE from electric eel (<em>Electrophorus electricusem> L.. Experimental lipophilicity was determined, and the structure-activity relationships are discussed. The mode of binding in the active site of AChE was investigated by molecular docking. All the discussed compounds expressed significantly higher AChE inhibitory activity than rivastigmine and slightly lower than galanthamine. Disubstitution by chlorine in C'_{(3,4} of the aniline ring and the optimal length of hexyl-undecyl alkyl chains in the carbamate moiety provided the most active AChE inhibitors. Monochlorination in C'_{(4} exhibited slightly more effective AChE inhibitors than in C'_{(3}. Generally it can be stated that compounds with higher lipophilicity showed higher inhibition, and the activity of the compounds is strongly dependent on the length of the <em>N>-alkyl chain.
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Eric Costello
2011-01-01
Full Text Available The shape of a cable hanging under its own weight and uniform horizontal tension between two power poles is a catenary. The catenary is a curve which has an equation defined by a hyperbolic cosine function and a scaling factor. The scaling factor for power cables hanging under their own weight is equal to the horizontal tension on the cable divided by the weight of the cable. Both of these values are unknown for this problem. Newton's method was used to approximate the scaling factor and the arc length function to determine the length of the cable. A script was written using the Python programming language in order to quickly perform several iterations of Newton's method to get a good approximation for the scaling factor.
INTERPOLATION WITH RESTRICTED ARC LENGTH
Institute of Scientific and Technical Information of China (English)
Petar Petrov
2003-01-01
For given data (ti,yi), I= 0,1,…,n,0 = t0 ＜t1 ＜…＜tn = 1we study constrained interpolation problem of Favard type inf{‖f"‖∞|f∈W2∞[0,1],f(ti)=yi,i=0,…,n,l(f;[0,1])≤l0}, wherel(f";[0,1])=∫1 0 / 1+f'2(x)dx is the arc length off in [0,1]. We prove the existence of a solution f* of the above problem, that is a quadratic spline with a second derivative f"* , which coincides with one of the constants - ‖f"*‖∞,0,‖f"*‖∞ between every two consecutive knots. Thus, we extend a result ofKarlin concerning Favard problem, to the case of restricted length interpolation.
Minimal Length, Measurability and Gravity
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Alexander Shalyt-Margolin
2016-03-01
Full Text Available The present work is a continuation of the previous papers written by the author on the subject. In terms of the measurability (or measurable quantities notion introduced in a minimal length theory, first the consideration is given to a quantum theory in the momentum representation. The same terms are used to consider the Markov gravity model that here illustrates the general approach to studies of gravity in terms of measurable quantities.
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Sreenivasan Sasidharan
2012-04-01
Full Text Available The urgent need to treat multi-drug resistant pathogenic microorganisms in chronically infected patients has given rise to the development of new antimicrobials from natural resources. We have tested <em>Elaeis guineensis em>Jacq> em>(Arecaceae methanol extract against a variety of bacterial, fungal and yeast strains associated with infections. Our studies have demonstrated that <em>E. guineensisem> exhibits excellent antimicrobial activity <em>in vitroem> and <em>in vivoem> against the bacterial and fungal strains tested. A marked inhibitory effect of the <em>E. guineensisem> extracts was observed against <em>C. albicansem> whereby <em>E. guineensisem> extract at ½, 1, or 2 times the MIC significantly inhibited <em>C. albicansem> growth with a noticeable drop in optical density (OD of the bacterial culture. This finding confirmed the anticandidal activity of the extract on <em>C. albicansem>. Imaging using scanning (SEM and transmission (TEM electron microscopy was done to determine the major alterations in the microstructure of the extract-treated <em>C. albicansem>. The main abnormalities noted via SEM and TEM studies were the alteration in morphology of the yeast cells. <em>In vivoem> antimicrobial activity was studies in mice that had been inoculated with <em>C. albicansem> and exhibited good anticandidal activity. The authors conclude that the extract may be used as a candidate for the development of anticandidal agent.<em> em>
Algorithms for Computing Triangular Decompositions of Polynomial Systems
Chen, Changbo
2011-01-01
We propose new algorithms for computing triangular decompositions of polynomial systems incrementally. With respect to previous works, our improvements are based on a {\\em weakened} notion of a polynomial GCD modulo a regular chain, which permits to greatly simplify and optimize the sub-algorithms. Extracting common work from similar expensive computations is also a key feature of our algorithms. In our experimental results the implementation of our new algorithms, realized with the {\\RegularChains} library in {\\Maple}, outperforms solvers with similar specifications by several orders of magnitude on sufficiently difficult problems.
Investigating Performance of Various Natural Computing Algorithms
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Bharat V. Chawda
2017-01-01
Full Text Available Nature is there since millenniums. Natural elements have withstood harsh complexities since years and have proved their efficiency in tackling them. This aspect has inspired many researchers to design algorithms based on phenomena in the natural world since the last couple of decades. Such algorithms are known as natural computing algorithms or nature inspired algorithms. These algorithms have established their ability to solve a large number of real-world complex problems by providing optimal solutions within the reasonable time duration. This paper presents an investigation by assessing the performance of some of the well-known natural computing algorithms with their variations. These algorithms include Genetic Algorithms, Ant Colony Optimization, River Formation Dynamics, Firefly Algorithm and Cuckoo Search. The Traveling Sales man Problem is used here as a test bed problem for performance evaluation of these algorithms. It is a kind of combinatorial optimization problem and known as one the most famous NP-Hard problems. It is simple and easy to understand, but at the same time, very difficult to find the optimal solution in a reasonable time – particularly with the increase in a number of cities. The source code for the above natural computing algorithms is developed in MATLAB R2015b and applied on several TSP instances given in TSPLIB library. Results obtained are analyzed based on various criteria such as tour length, required iterations, convergence time and quality of solutions. Conclusions derived from this analysis help to establish the superiority of Firefly Algorithms over the other algorithms in comparative terms.
A decoding method of an n length binary BCH code through (n + 1n length binary cyclic code
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TARIQ SHAH
2013-09-01
Full Text Available For a given binary BCH code Cn of length n = 2 s - 1 generated by a polynomial of degree r there is no binary BCH code of length (n + 1n generated by a generalized polynomial of degree 2r. However, it does exist a binary cyclic code C (n+1n of length (n + 1n such that the binary BCH code Cn is embedded in C (n+1n . Accordingly a high code rate is attained through a binary cyclic code C (n+1n for a binary BCH code Cn . Furthermore, an algorithm proposed facilitates in a decoding of a binary BCH code Cn through the decoding of a binary cyclic code C (n+1n , while the codes Cn and C (n+1n have the same minimum hamming distance.
A Learning Algorithm for Multimodal Grammar Inference.
D'Ulizia, A; Ferri, F; Grifoni, P
2011-12-01
The high costs of development and maintenance of multimodal grammars in integrating and understanding input in multimodal interfaces lead to the investigation of novel algorithmic solutions in automating grammar generation and in updating processes. Many algorithms for context-free grammar inference have been developed in the natural language processing literature. An extension of these algorithms toward the inference of multimodal grammars is necessary for multimodal input processing. In this paper, we propose a novel grammar inference mechanism that allows us to learn a multimodal grammar from its positive samples of multimodal sentences. The algorithm first generates the multimodal grammar that is able to parse the positive samples of sentences and, afterward, makes use of two learning operators and the minimum description length metrics in improving the grammar description and in avoiding the over-generalization problem. The experimental results highlight the acceptable performances of the algorithm proposed in this paper since it has a very high probability of parsing valid sentences.
Radix-3 Algorithm for Realization of Discrete Fourier Transform
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M.Narayan Murty
2016-07-01
Full Text Available In this paper, a new radix-3 algorithm for realization of discrete Fourier transform (DFT of length N = 3m (m = 1, 2, 3,... is presented. The DFT of length N can be realized from three DFT sequences, each of length N/3. If the input signal has length N, direct calculation of DFT requires O (N 2 complex multiplications (4N 2 real multiplications and some additions. This radix-3 algorithm reduces the number of multiplications required for realizing DFT. For example, the number of complex multiplications required for realizing 9-point DFT using the proposed radix-3 algorithm is 60. Thus, saving in time can be achieved in the realization of proposed algorithm.
Ternary Tree and Memory-Efficient Huffman Decoding Algorithm
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Pushpa R. Suri
2011-01-01
Full Text Available In this study, the focus was on the use of ternary tree over binary tree. Here, a new one pass Algorithm for Decoding adaptive Huffman ternary tree codes was implemented. To reduce the memory size and fasten the process of searching for a symbol in a Huffman tree, we exploited the property of the encoded symbols and proposed a memory efficient data structure to represent the codeword length of Huffman ternary tree. In this algorithm we tried to find out the staring and ending address of the code to know the length of the code. And then in second algorithm we tried to decode the ternary tree code using binary search method. In this algorithm we tried to find out the staring and ending address of the code to know the length of the code. And then in second algorithm we tried to decode the ternary tree code using binary search method.
Holst, Glendon
2016-12-01
Serial section electron microscopy (SSEM) image stacks generated using high throughput microscopy techniques are an integral tool for investigating brain connectivity and cell morphology. FIB or 3View scanning electron microscopes easily generate gigabytes of data. In order to produce analyzable 3D dataset from the imaged volumes, efficient and reliable image segmentation is crucial. Classical manual approaches to segmentation are time consuming and labour intensive. Semiautomatic seeded watershed segmentation algorithms, such as those implemented by ilastik image processing software, are a very powerful alternative, substantially speeding up segmentation times. We have used ilastik effectively for small EM stacks – on a laptop, no less; however, ilastik was unable to carve the large EM stacks we needed to segment because its memory requirements grew too large – even for the biggest workstations we had available. For this reason, we refactored the carving module of ilastik to scale it up to large EM stacks on large workstations, and tested its efficiency. We modified the carving module, building on existing blockwise processing functionality to process data in manageable chunks that can fit within RAM (main memory). We review this refactoring work, highlighting the software architecture, design choices, modifications, and issues encountered.
Algorithm Animation with Galant.
Stallmann, Matthias F
2017-01-01
Although surveys suggest positive student attitudes toward the use of algorithm animations, it is not clear that they improve learning outcomes. The Graph Algorithm Animation Tool, or Galant, challenges and motivates students to engage more deeply with algorithm concepts, without distracting them with programming language details or GUIs. Even though Galant is specifically designed for graph algorithms, it has also been used to animate other algorithms, most notably sorting algorithms.
Gao, Simon S.; Liu, Li; Bailey, Steven T.; Flaxel, Christina J.; Huang, David; Li, Dengwang; Jia, Yali
2016-07-01
Quantification of choroidal neovascularization (CNV) as visualized by optical coherence tomography angiography (OCTA) may have importance clinically when diagnosing or tracking disease. Here, we present an automated algorithm to quantify the vessel skeleton of CNV as vessel length. Initial segmentation of the CNV on en face angiograms was achieved using saliency-based detection and thresholding. A level set method was then used to refine vessel edges. Finally, a skeleton algorithm was applied to identify vessel centerlines. The algorithm was tested on nine OCTA scans from participants with CNV and comparisons of the algorithm's output to manual delineation showed good agreement.
Efficient Heterologous Transformation of <em>Chlamydomonas> reinhardtiiem> <em>npq2em> Mutant with the Zeaxanthin Epoxidase Gene Isolated and Characterized from<em> Chlorella zofingiensisem>
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Herminia Rodríguez
2012-09-01
Full Text Available In the violaxanthin cycle, the violaxanthin de-epoxidase and zeaxanthin epoxidase catalyze the inter-conversion between violaxanthin and zeaxanthin in both plants and green algae. The zeaxanthin epoxidase gene from the green microalga <em>Chlorella zofingiensisem> (<em>Czzep> has been isolated<em>. em>This gene encodes a polypeptide of 596 amino acids. A single copy of <em>Czzep> has been found in the <em>C. zofingiensisem> genome by Southern blot analysis. qPCR analysis has shown that transcript levels of <em>Czzep> were increased after zeaxanthin formation under high light conditions. The functionality of <em>Czzep> gene by heterologous genetic complementation in the <em>Chlamydomonas> mutant <em>npq2em>, which lacks zeaxanthin epoxidase (ZEP activity and accumulates zeaxanthin in all conditions, was analyzed. The <em>Czzep> gene was adequately inserted in the pSI105 vector and expressed in <em>npq2em>. The positive transformants were able to efficiently convert zeaxanthin into violaxanthin, as well as to restore their maximum quantum efficiency of the PSII (Fv/Fm. These results show that <em>Chlamydomonas> can be an efficient tool for heterologous expression and metabolic engineering for biotechnological applications.
On the occurrence of <em>Myotis alcathoeem> von Helversen and Heller, 2001 in Austria
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Friederike Spitzenberger
2008-07-01
Full Text Available Abstract In 2006, one male and two females of <em>Myotis alcathoeem> were captured in mistnets at two localities in southern Burgenland, Austria. For two individuals the preliminary specific identification based on external measurements was confirmed by sequencing parts of the mitochondrial ND1 gene. Across the sequenced region, the two analysed bats share a 100% identical haplotype that corresponds to the haplotype found in Hungarian bats identified as <em>M. alcathoeem>, and was found also in Spanish, French and Slovakian samples. The three animals from Burgenland constitute the first records of this species in Austria. Age related differences in pelage and membrane colouration and measurements of <em>M. alcathoeem> are described. A comparison of skull length measurements between <em>M. alcathoeem> and <em>Myotis mystacinusem> seems to indicate that the interspecific difference in external dimensions is not reflected in skull dimensions. The Austrian localities of <em>M. alcathoeem> belong to the Pannonian part of the range like findings in Slovakia and Hungary. Riassunto Sulla presenza di <em>Myotis alcathoeem> von Helversen and Heller, 2001 in Austria. Nel 2006, due maschi e una femmina di <em>Myotis alcathoeem> sono stati catturati tramite mist-nets in due località del Burgenland meridionale, Austria. Per due individui, l’identificazione preliminare su basi morfologiche è stata confermata dall’analisi del gene mitocondriale ND1. Nella sequenza analizzata, gli aplotipi dei due individui coincidono al 100% e corrispondono a quelli evidenziati in soggetti spagnoli, francesi e sloveni. I tre esemplari del Burgenland rappresentano la prima segnalazione certa di questa specie per l’Austria. Vengono descritte alcune differenze nella colorazione della pelliccia e del patagio tra adulti e subadulti. Il confronto delle misure del cranio di <em>M. alcathoeem> e <em
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Issa Ahmed Abed
2016-12-01
Full Text Available This paper present a method to enhance the firefly algorithm by coupling with a local search. The constructed technique is applied to identify the solar parameters model where the method has been proved its ability to obtain the photovoltaic parameters model. Standard firefly algorithm (FA, electromagnetism-like (EM algorithm, and electromagnetism-like without local (EMW search algorithm all are compared with the suggested method to test its capability to solve this model.
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Juan Eduardo Samur-San Martin
2011-06-01
Full Text Available A obesidade é considerada uma epidemia, que acomete também crianças e adolescentes com síndrome de Down. Contudo, como não há um parâmetro consensual para diagnosticar obesidade nessa população, o objetivo deste trabalho foi realizar uma revisão crítica de artigos que estudam índices antropométricos, para avaliação do estado nutricional de crianças e adolescentes com essa síndrome. O levantamento dos artigos foi realizado nas bases de dados PubMed, MedlLine, Lilacs e SciELO, dando-se importância aos parâmetros antropométricos e sua relação com a obesidade. De 83 artigos iniciais, foram selecionados 11 para análise crítica. Nos Estados Unidos, estabeleceram uma curva de normalidade para peso e estatura de crianças e adolescentes com síndrome de Down e, quando compararam os seus valores com as curvas do National Center for Health Statistics, observaram que houve um padrão menor de crescimento em estatura. Em estudos europeus, observou-se o mesmo fato. No Brasil, Mustacchi desenvolveu índices de peso/idade e estatura/idade e observou deficit importante de estatura, quando comparou estatura/idade com as curvas do National Center for Health Statistics e com as curvas de Cronk et al. Em CONCLUSÃO:, os dados antropométricos disponíveis em curvas pôndero-estaturais são considerados relativos a uma determinada população e revelam suas características específicas, porque expressam a influência dos fatores ambientais e determinantes genéticos. Portanto, há necessidade de se definir curvas de padrão de referência para crianças e adolescentes com síndrome de Down em diferentes faixas etárias, regiões e etnias, para se diagnosticar corretamente seu estado nutricional.Obesity is considered an epidemic and also affects children and adolescents with Down syndrome. However, since a consensual parameter for diagnosing obesity in this population does not exist, the objetive of this study was to perform a critical review
Image fusion based on expectation maximization algorithm and steerable pyramid
Institute of Scientific and Technical Information of China (English)
Gang Liu(刘刚); Zhongliang Jing(敬忠良); Shaoyuan Sun(孙韶媛); Jianxun Li(李建勋); Zhenhua Li(李振华); Henry Leung
2004-01-01
In this paper, a novel image fusion method based on the expectation maximization (EM) algorithm and steerable pyramid is proposed. The registered images are first decomposed by using steerable pyramid.The EM algorithm is used to fuse the image components in the low frequency band. The selection method involving the informative importance measure is applied to those in the high frequency band. The final fused image is then computed by taking the inverse transform on the composite coefficient representations.Experimental results show that the proposed method outperforms conventional image fusion methods.
Dermatoses em renais cronicos em terapia dialitica
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Luis Alberto Batista Peres
2014-03-01
Full Text Available Objetivo: As desordens cutâneas e das mucosas são comuns em pacientes em hemodiálise a longo prazo. A diálise prolonga a expectativa de vida, dando tempo para a manifestação destas anormalidades. Os objetivos deste estudo foram avaliar a prevalência de problemas dermatológicos em pacientes com doença renal crônica (DRC em hemodiálise. Métodos: Cento e quarenta e cinco pacientes com doença renal crônica em hemodiálise foram estudados. Todos os pacientes foram completamente analisados para as alterações cutâneas, de cabelos, mucosas e unhas por um único examinador e foram coletados dados de exames laboratoriais. Os dados foram armazenados em um banco de dados do Microsolft Excel e analisados por estatística descritiva. As variáveis contínuas foram comparadas pelo teste t de Student e as variáveis categóricas utilizando o teste do qui-quadrado ou o teste Exato de Fischer, conforme adequado. Resultados: O estudo incluiu 145 pacientes, com idade média de 53,6 ± 14,7 anos, predominantemente do sexo masculino (64,1% e caucasianos (90,0%. O tempo médio de diálise foi de 43,3 ± 42,3 meses. As principais doenças subjacentes foram: hipertensão arterial em 33,8%, diabetes mellitus em 29,6% e glomerulonefrite crônica em 13,1%. As principais manifestações dermatológicas observadas foram: xerose em 109 (75,2%, equimose em 87 (60,0%, prurido em 78 (53,8% e lentigo em 33 (22,8% pacientes. Conclusão: O nosso estudo mostrou a presença de mais do que uma dermatose por paciente. As alterações cutâneas são frequentes em pacientes em diálise. Mais estudos são necessários para melhor caracterização e manejo destas dermatoses.
Osterberg, E C; Maganty, A; Ramasamy, R; Eid, J F
2014-01-01
Inflatable penile prosthesis (IPP) remains the gold standard for the surgical treatment of refractory erectile dysfunction; however, current literature to aid surgeons on how best to counsel patients on their postoperative inflated penile length is lacking. The aim of this study was to identify preoperative parameters that could better predict postoperative penile length following insertion of an IPP. Twenty men were enrolled in a prospective study examining penile lengths before and after IPP surgery. Patients with Peyronie's disease were excluded from this analysis. Baseline preoperative characteristics, including body mass index, history of hypertension, diabetes, Sexual Health Inventory for Men scores and/or prior radical prostatectomy were recorded. All patients underwent implantation with a three-piece inflatable Coloplast penile prosthesis. We compared stretched penile length to pharmacologically induced erect lengths. Postoperatively, we measured inflated penile lengths at 6 weeks and assessed patients' perception of penile size at 12 weeks. The median (±interquartile range) stretched penile length and pharmacologically induced erect penile length was 15 (±3) and 14.25 (±2) cm, respectively (P=0.5). Median post-prosthesis penile length (13.5±2.13 cm) was smaller than preoperative pharmacologically induced length (P=0.02) and preoperative stretched penile length (P=0.01). The majority of patients (70%) had a decrease in penile length (median loss 0.5±1.5 cm); however, this loss was perceptible by 43% of men. Stretched penile length and pharmacologically induced erect penile length were equally good predictors of postoperative inflated length (Spearman's correlation 0.8 and 0.9, respectively). Pharmacologically induced erect penile length and stretched penile lengths are equal predictors of post-prosthesis penile length. The majority of men will experience some decrease in penile length following prosthesis implantation; however <50% report a
Testing of Cotton Fiber Length
Institute of Scientific and Technical Information of China (English)
刘若华; 李汝勤
2001-01-01
To understand the influences of actual sampling conditions on cotton fiber length testing, this article presents a theoretic study on the distributions and fibrogram of the sample taken out by sampler from ideal sliver at a certain angle. From the distributions expression it can be found that the size of the sampler and the sampling angle are important factors which affect sampling, but if the sampling width is narrow enough, the influence of the sampling angle on the distributions and fibrogram is small enough to be omitted. This is an important conclusion for sampling, in light of this, some suggestions for designing new type sampler are put forward.
Comparison of turbulence mitigation algorithms
Kozacik, Stephen T.; Paolini, Aaron; Sherman, Ariel; Bonnett, James; Kelmelis, Eric
2017-07-01
When capturing imagery over long distances, atmospheric turbulence often degrades the data, especially when observation paths are close to the ground or in hot environments. These issues manifest as time-varying scintillation and warping effects that decrease the effective resolution of the sensor and reduce actionable intelligence. In recent years, several image processing approaches to turbulence mitigation have shown promise. Each of these algorithms has different computational requirements, usability demands, and degrees of independence from camera sensors. They also produce different degrees of enhancement when applied to turbulent imagery. Additionally, some of these algorithms are applicable to real-time operational scenarios while others may only be suitable for postprocessing workflows. EM Photonics has been developing image-processing-based turbulence mitigation technology since 2005. We will compare techniques from the literature with our commercially available, real-time, GPU-accelerated turbulence mitigation software. These comparisons will be made using real (not synthetic), experimentally obtained data for a variety of conditions, including varying optical hardware, imaging range, subjects, and turbulence conditions. Comparison metrics will include image quality, video latency, computational complexity, and potential for real-time operation. Additionally, we will present a technique for quantitatively comparing turbulence mitigation algorithms using real images of radial resolution targets.
Genetic analysis of growth curves using the SAEM algorithm
Directory of Open Access Journals (Sweden)
Lavielle Marc
2006-11-01
Full Text Available Abstract The analysis of nonlinear function-valued characters is very important in genetic studies, especially for growth traits of agricultural and laboratory species. Inference in nonlinear mixed effects models is, however, quite complex and is usually based on likelihood approximations or Bayesian methods. The aim of this paper was to present an efficient stochastic EM procedure, namely the SAEM algorithm, which is much faster to converge than the classical Monte Carlo EM algorithm and Bayesian estimation procedures, does not require specification of prior distributions and is quite robust to the choice of starting values. The key idea is to recycle the simulated values from one iteration to the next in the EM algorithm, which considerably accelerates the convergence. A simulation study is presented which confirms the advantages of this estimation procedure in the case of a genetic analysis. The SAEM algorithm was applied to real data sets on growth measurements in beef cattle and in chickens. The proposed estimation procedure, as the classical Monte Carlo EM algorithm, provides significance tests on the parameters and likelihood based model comparison criteria to compare the nonlinear models with other longitudinal methods.
Directory of Open Access Journals (Sweden)
Cristina Rodríguez-Padilla
2012-09-01
Full Text Available Bioassay-guided fractionation of hexane extracts of<em> Gymnosperma glutinosumem> (Asteraceae leaves, collected in North Mexico, afforded the known compounds hentriacontane (1 and (+-13<em>S>,14<em>R>,15-trihydroxy-<em>ent>-labd-7-ene (2, as well as the new <em>ent>-labdane diterpene (−-13<em>S>,14<em>R>,15-trihydroxy-7-oxo-<em>ent>-labd-8(9-ene (3. In addition, D-glycero-D-galactoheptitol (4 was isolated from the methanolic extract of this plant. Their structures were established on the basis of high-field 1D- and 2D NMR methods supported by HR-MS data. The cytotoxic activity was determined by using the <em>in vitroem> L5178Y-R lymphoma murine model. Hentriacontane (1 and the new <em>ent>-labdane 3 showed weak cytotoxicity, whereas the <em>ent>-labdane 2 showed significant (<em>p> < 0.05 and concentration dependent cytotoxicity (up to 78% against L5178Y-R cells at concentrations ranging from 7.8 to 250 µg/mL.
Generalizations of Brandl's theorem on Engel length
Quek, S. G.; Wong, K. B.; Wong, P. C.
2013-04-01
Let n Engel cycle generated by g and h. The length of the Engel cycle is m-n. A group G is said to have Engel length r, if all the length of the Engel cycles in G divides r. In this paper we discuss the Brandl's theorem on Engel length and give some of its generalizations.
Image Compression using GSOM Algorithm
Directory of Open Access Journals (Sweden)
SHABBIR AHMAD
2015-10-01
Full Text Available
Directory of Open Access Journals (Sweden)
Ana Maria Sala Minucci Martins
2006-01-01
Full Text Available Está sendo desenvolvido projeto de pesquisa denominado Geometria Fractal e suas Aplicações em Arquitetura e Urbanismo, com o fito de estudar e desenvolver ferramentas analíticas e propositivas para serem aplicadas em arquitetura e urbanismo, com base em conceitos provenientes da geometria fractal.
Smoothed analysis of partitioning algorithms for Euclidean functionals
Bläser, Markus; Manthey, Bodo; Rao, B.V. Raghavendra
2013-01-01
Euclidean optimization problems such as TSP and minimum-length matching admit fast partitioning algorithms that compute near-optimal solutions on typical instances. In order to explain this performance, we develop a general framework for the application of smoothed analysis to partitioning algorithm
Smoothed analysis of partitioning algorithms for Euclidean functionals
Bläser, Markus; Manthey, Bodo; Rao, B.V. Raghavendra; Dehne, F.; Iacono, J.; Sack, J.-R.
2011-01-01
Euclidean optimization problems such as TSP and minimum-length matching admit fast partitioning algorithms that compute near-optimal solutions on typical instances. We develop a general framework for the application of smoothed analysis to partitioning algorithms for Euclidean optimization problems.
Online learning algorithm for ensemble of decision rules
Chikalov, Igor
2011-01-01
We describe an online learning algorithm that builds a system of decision rules for a classification problem. Rules are constructed according to the minimum description length principle by a greedy algorithm or using the dynamic programming approach. © 2011 Springer-Verlag.
Directory of Open Access Journals (Sweden)
Monika Sienkiewicz
2012-08-01
Full Text Available The aim of this work was to investigate the antibacterial properties of geranium oil obtained from <em>Pelargonium graveolensem> Ait. (family <em>Geraniaceae>, against one standard <em>S. aureus em>strain ATCC 433000 and seventy clinical <em>S. aureusem> strains. The agar dilution method was used for assessment of bacterial growth inhibition at various concentrations of geranium oil. Susceptibility testing of the clinical strains to antibiotics was carried out using the disk-diffusion and E-test methods. The results of our experiment showed that the oil from <em>P. graveolensem> has strong activity against all of the clinical <em>S. aureusem> isolates—including multidrug resistant strains, MRSA strains and MLS_{B}-positive strains—exhibiting MIC values of 0.25–2.50 μL/mL.
Comparative Study of Static Task Scheduling Algorithms for Heterogeneous Systems
Directory of Open Access Journals (Sweden)
Miss. Kalpana A. Manudhane
2013-03-01
Full Text Available On the distributed or parallel heterogeneous computing systems, an application is usually decomposed into several interdependent sets of co-operating subtasks and assigned to a set of available processors for execution. Task scheduling is in general NP-compete problem. Static task scheduling algorithms are categorized as Heuristic based and Guided random search based scheduling algorithms. Heuristic algorithms guaranteed to find near optimal solution in less than polynomial time. Heuristic based list scheduling algorithms are Heterogeneous Earliest Finish Time (HEFT and Critical-Path-On- -Processor (CPOP. Whereas, Guided random search based scheduling algorithms have shown robust performance on verity of schedulingproblems. Typical examples are Multiple Priority Queueing Genetic Algorithm (MPQGA, Tabu Search(TS, Ant Colony System (ACS. This paper gives comparative study of all these static task scheduling algorithms and compares them on the basis of average makespan, schedule length ratio (SLR and speedup and running time of algorithm.
Upper Bound for Queue length in Regulated Burst Service Scheduling
Directory of Open Access Journals (Sweden)
Mahmood Daneshvar Farzanegan
2016-01-01
Full Text Available Quality of Service (QoS provisioning is very important in next computer/communication networks because of increasing multimedia services. Hence, very investigations are performed in this area. Scheduling algorithms effect QoS provisioning. Lately, a scheduling algorithm called Regulated Burst Service Scheduling (RBSS suggested by author in [1] to provide a better service to bursty and delay sensitive services such as video. One of the most significant feature in RBSS is considering burstiness of arrival traffic in scheduling algorithm. In this paper, an upper bound of queue length or buffer size and service curve are calculated by Network Calculus analysis for RBSS. Because in RBSS queue length is a parameter that is considered in scheduling arbitrator, analysis results a differential inequality to obtain service curve. To simplify, arrival traffic is assumed to be linear that is defined in the paper clearly. This paper help to analysis delay in RBSS for different traffic with different specifications. Therefore, QoS provisioning will be evaluated.
ROUTING ALGORITHM FOR THE ROTATION-EXCHANGE NETWORK
Institute of Scientific and Technical Information of China (English)
Chen Baoxing; Xiao Wenjun
2005-01-01
The paper proposes a new routing algorithm for the Rotation-Exchange (REn) network. The length of the path between any two nodes given by the algorithm is not more than (3/8)n2 + O(n), that is, the diameter of REa is not more than (3/8)n2 + O(n). This improves on a (1/2)n2 + O(n) routing algorithm proposed earlier.
TOA estimation algorithm based on multi-search
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
A new time of arrival (TOA) estimation algorithm is proposed. The algorithm computes the optimal sub-correlation length based on the SNR theory. So the robust of TOA acquirement is guaranteed very well. Then, according to the actual transmission environment and network system, the multi-search method is given. From the simulation result,the algorithm shows a very high application value in the realization of wireless location system (WLS).
Comparison of reconfigurable structures for flexible word-length multiplication
Directory of Open Access Journals (Sweden)
O. A. Pfänder
2008-05-01
Full Text Available Binary multiplication continues to be one of the essential arithmetic operations in digital circuits. Even though field-programmable gate arrays (FPGAs are becoming more and more powerful these days, the vendors cannot avoid implementing multiplications with high word-lengths using embedded blocks instead of configurable logic. But on the other hand, the circuit's efficiency decreases if the provided word-length of the hard-wired multipliers exceeds the precision requirements of the algorithm mapped into the FPGA. Thus it is beneficial to use multiplier blocks with configurable word-length, optimized for area, speed and power dissipation, e.g. regarding digital signal processing (DSP applications.
In this contribution, we present different approaches and structures for the realization of a multiplication with variable precision and perform an objective comparison. This includes one approach based on a modified Baugh and Wooley algorithm and three structures using Booth's arithmetic operand recoding with different array structures. All modules have the option to compute signed two's complement fix-point numbers either as an individual computing unit or interconnected to a superior array. Therefore, a high throughput at low precision through parallelism, or a high precision through concatenation can be achieved.
Skiena, Steven S
2008-01-01
Explaining designing algorithms, and analyzing their efficacy and efficiency, this book covers combinatorial algorithms technology, stressing design over analysis. It presents instruction on methods for designing and analyzing computer algorithms. It contains the catalog of algorithmic resources, implementations and a bibliography
Hamiltonian Algorithm Sound Synthesis
大矢, 健一
2013-01-01
Hamiltonian Algorithm (HA) is an algorithm for searching solutions is optimization problems. This paper introduces a sound synthesis technique using Hamiltonian Algorithm and shows a simple example. "Hamiltonian Algorithm Sound Synthesis" uses phase transition effect in HA. Because of this transition effect, totally new waveforms are produced.
Walker, Matthew G; Olszewski, Edward W; Sen, Bodhisattva; Woodroofe, Michael
2008-01-01
(abridged) We develop an algorithm for estimating parameters of a distribution sampled with contamination, employing a statistical technique known as ``expectation maximization'' (EM). Given models for both member and contaminant populations, the EM algorithm iteratively evaluates the membership probability of each discrete data point, then uses those probabilities to update parameter estimates for member and contaminant distributions. The EM approach has wide applicability to the analysis of astronomical data. Here we tailor an EM algorithm to operate on spectroscopic samples obtained with the Michigan-MIKE Fiber System (MMFS) as part of our Magellan survey of stellar radial velocities in nearby dwarf spheroidal (dSph) galaxies. These samples are presented in a companion paper and contain discrete measurements of line-of-sight velocity, projected position, and Mg index for ~1000 - 2500 stars per dSph, including some fraction of contamination by foreground Milky Way stars. The EM algorithm quantifies both dSp...
Ilic, Velimir M; Todorovic, Branimir T; Stankovic, Miomir S
2010-01-01
The paper proposes a new recursive algorithm for the exact computation of the linear chain conditional random fields gradient. The algorithm is an instance of the Entropy Message Passing (EMP), introduced in our previous work, and has the purpose to enhance memory efficiency when applied to long observation sequences. Unlike the traditional algorithm based on the forward and the backward recursions, the memory complexity of our algorithm does not depend on the sequence length, having the same computational complexity as the standard algorithm.
DEFF Research Database (Denmark)
Bucher, Taina
2017-01-01
of algorithms affect people's use of these platforms, if at all? To help answer these questions, this article examines people's personal stories about the Facebook algorithm through tweets and interviews with 25 ordinary users. To understand the spaces where people and algorithms meet, this article develops...... the notion of the algorithmic imaginary. It is argued that the algorithmic imaginary – ways of thinking about what algorithms are, what they should be and how they function – is not just productive of different moods and sensations but plays a generative role in moulding the Facebook algorithm itself...
Energy Technology Data Exchange (ETDEWEB)
Geist, G.A. [Oak Ridge National Lab., TN (United States). Computer Science and Mathematics Div.; Howell, G.W. [Florida Inst. of Tech., Melbourne, FL (United States). Dept. of Applied Mathematics; Watkins, D.S. [Washington State Univ., Pullman, WA (United States). Dept. of Pure and Applied Mathematics
1997-11-01
The BR algorithm, a new method for calculating the eigenvalues of an upper Hessenberg matrix, is introduced. It is a bulge-chasing algorithm like the QR algorithm, but, unlike the QR algorithm, it is well adapted to computing the eigenvalues of the narrowband, nearly tridiagonal matrices generated by the look-ahead Lanczos process. This paper describes the BR algorithm and gives numerical evidence that it works well in conjunction with the Lanczos process. On the biggest problems run so far, the BR algorithm beats the QR algorithm by a factor of 30--60 in computing time and a factor of over 100 in matrix storage space.
Energy Technology Data Exchange (ETDEWEB)
1993-07-01
It is the intent of EM International to describe the Office of Environmental Restoration and Waste Management`s (EM`s) various roles and responsibilities within the international community. Cooperative agreements and programs, descriptions of projects and technologies, and synopses of visits to international sites are all highlighted in this semiannual journal. Focus on EM programs in this issue is on international collaboration in vitrification projects. Technology highlights covers: in situ sealing for contaminated sites; and remote sensors for toxic pollutants. Section on profiles of countries includes: Arctic contamination by the former Soviet Union, and EM activities with Germany--cooperative arrangements.
An approach to operational modal analysis using the expectation maximization algorithm
Cara, F. Javier; Carpio, Jaime; Juan, Jesús; Alarcón, Enrique
2012-08-01
This paper presents the Expectation Maximization algorithm (EM) applied to operational modal analysis of structures. The EM algorithm is a general-purpose method for maximum likelihood estimation (MLE) that in this work is used to estimate state space models. As it is well known, the MLE enjoys some optimal properties from a statistical point of view, which make it very attractive in practice. However, the EM algorithm has two main drawbacks: its slow convergence and the dependence of the solution on the initial values used. This paper proposes two different strategies to choose initial values for the EM algorithm when used for operational modal analysis: to begin with the parameters estimated by Stochastic Subspace Identification method (SSI) and to start using random points. The effectiveness of the proposed identification method has been evaluated through numerical simulation and measured vibration data in the context of a benchmark problem. Modal parameters (natural frequencies, damping ratios and mode shapes) of the benchmark structure have been estimated using SSI and the EM algorithm. On the whole, the results show that the application of the EM algorithm starting from the solution given by SSI is very useful to identify the vibration modes of a structure, discarding the spurious modes that appear in high order models and discovering other hidden modes. Similar results are obtained using random starting values, although this strategy allows us to analyze the solution of several starting points what overcome the dependence on the initial values used.
Algorithmically specialized parallel computers
Snyder, Lawrence; Gannon, Dennis B
1985-01-01
Algorithmically Specialized Parallel Computers focuses on the concept and characteristics of an algorithmically specialized computer.This book discusses the algorithmically specialized computers, algorithmic specialization using VLSI, and innovative architectures. The architectures and algorithms for digital signal, speech, and image processing and specialized architectures for numerical computations are also elaborated. Other topics include the model for analyzing generalized inter-processor, pipelined architecture for search tree maintenance, and specialized computer organization for raster
A new hybrid imperialist competitive algorithm on data clustering
Indian Academy of Sciences (India)
Taher Niknam; Elahe Taherian Fard; Shervin Ehrampoosh; Alireza Rousta
2011-06-01
Clustering is a process for partitioning datasets. This technique is very useful for optimum solution. -means is one of the simplest and the most famous methods that is based on square error criterion. This algorithm depends on initial states and converges to local optima. Some recent researches show that -means algorithm has been successfully applied to combinatorial optimization problems for clustering. In this paper, we purpose a novel algorithm that is based on combining two algorithms of clustering; -means and Modify Imperialist Competitive Algorithm. It is named hybrid K-MICA. In addition, we use a method called modiﬁed expectation maximization (EM) to determine number of clusters. The experimented results show that the new method carries out better results than the ACO, PSO, Simulated Annealing (SA), Genetic Algorithm (GA), Tabu Search (TS), Honey Bee Mating Optimization (HBMO) and -means.
Directory of Open Access Journals (Sweden)
André Luiz Galo
2009-01-01
Full Text Available We describe the design and tests of a set-up mounted in a conventional double beam spectrophotometer, which allows the determination of optical density of samples confined in a long liquid core waveguide (LCW capillary. Very long optical path length can be achieved with capillary cell, allowing measurements of samples with very low optical densities. The device uses a custom optical concentrator optically coupled to LCW (TEFLON® AF. Optical density measurements, carried out using a LCW of ~ 45 cm, were in accordance with the Beer-Lambert Law. Thus, it was possible to analyze quantitatively samples at concentrations 45 fold lower than that regularly used in spectrophotometric measurements.
Directory of Open Access Journals (Sweden)
José Gabriel Segarra-Moragues
2012-09-01
Full Text Available Polymorphic microsatellite markers were developed for the Ibero-North African, strict gypsophyte <em>Lepidium subulatumem> to unravel the effects of habitat fragmentation in levels of genetic diversity, genetic structure and gene flow among its populations. Using 454 pyrosequencing 12 microsatellite loci including di- and tri-nucleotide repeats were characterized in <em>L. subulatumem>. They amplified a total of 80 alleles (2–12 alleles per locus in a sample of 35 individuals of <em>L. subulatumem>, showing relatively high levels of genetic diversity, <em>H>_{O} = 0.645, <em>H>_{E} = 0.627. Cross-species transferability of all 12 loci was successful for the Iberian endemics <em>Lepidium cardaminesem>, <em>Lepidium stylatumem>, and the widespread, <em>Lepidium graminifoliumem> and one species each of two related genera, <em>Cardaria drabaem> and <em>Coronopus didymusem>. These microsatellite primers will be useful to investigate genetic diversity, population structure and to address conservation genetics in species of <em>Lepidium>.
New Trifluoromethyl Triazolopyrimidines as Anti-<em>Plasmodium> <em>falciparum> Agents
Directory of Open Access Journals (Sweden)
Núbia Boechat
2012-07-01
Full Text Available According to the World Health Organization, half of the World’s population, approximately 3.3 billion people, is at risk for developing malaria. Nearly 700,000 deaths each year are associated with the disease. Control of the disease in humans still relies on chemotherapy. Drug resistance is a limiting factor, and the search for new drugs is important. We have designed and synthesized new 2-(trifluoromethyl[1,2,4]triazolo[1,5-<em>a>]pyrimidine derivatives based on bioisosteric replacement of functional groups on the anti-malarial compounds mefloquine and amodiaquine. This approach enabled us to investigate the impact of: (i ring bioisosteric replacement; (ii a CF_{3} group substituted at the 2-position of the [1,2,4]triazolo[1,5-<em>a>]pyrimidine scaffold and (iii a range of amines as substituents at the 7-position of the of heterocyclic ring; on <em>in vitroem> activity against <em>Plasmodium falciparumem>. According to docking simulations, the synthesized compounds are able to interact with <em>P. falciparumem> dihydroorotate dehydrogenase (<em>Pf>DHODH through strong hydrogen bonds. The presence of a trifluoromethyl group at the 2-position of the [1,2,4]triazolo[1,5-<em>a>]pyrimidine ring led to increased drug activity. Thirteen compounds were found to be active, with IC_{50} values ranging from 0.023 to 20 µM in the anti-HRP2 and hypoxanthine assays. The selectivity index (SI of the most active derivatives 5, 8, 11 and 16 was found to vary from 1,003 to 18,478.
DEFF Research Database (Denmark)
Hobolth, Asger
2008-01-01
-dependent substitution models are analytically intractable and must be analyzed using either approximate or simulation-based methods. We describe statistical inference of neighbor-dependent models using a Markov chain Monte Carlo expectation maximization (MCMC-EM) algorithm. In the MCMC-EM algorithm, the high...
Directory of Open Access Journals (Sweden)
Joab Trajano Silva
2008-12-01
Full Text Available Mycobacterium bovis é membro do complexo Mycobacterium tuberculosis (MTBC, grupo este composto por espécies com grande homologia genética. É o agente etiológico da tuberculose bovina, importante zoonose transmissível ao homem, principalmente através da inalação do bacilo e/ou pelo consumo de leite e derivados não-pasteurizados provenientes de vacas tuberculosas. O objetivo deste estudo foi padronizar a identificação de micobactérias do complexo M. tuberculosis presentes no leite, por metodologia molecular. Fez-se a extração de DNA diretamente do leite contaminado e realizou-se a identificação molecular pela reação em cadeia da polimerase seguida de análise de restrição do fragmento amplificado (PRA. Utilizaram-se inhagens de referência e leite cru artificialmente contaminado com M. bovis IP. Um fragmento de 441pb do gene hsp65 foi amplificado, tratado com BstEII e HaeIII e empregou-se o perfil de restrição enzimática obtido para identificar o complexo M. tuberculosis no leite. Com a PRA foi possível detectar com especificidade e sensibilidade a presença de M. bovis em até 10 UFC/mL de leite. A metodologia padronizada poderá auxiliar os métodos microbiológicos e bioquímicos tradicionalmente usados na identificação do bacilo em alimentos suspeitos de contaminação, como, por exemplo, o leite proveniente de animais suspeitos de infecção por M. bovis.
Palavras-chaves: Análise de perfil de restrição enzimática (PRA, complexo Mycobacterium tuberculosis, leite, Mycobacterium bovis, limite de detecção (PCR. Mycobacterium bovis is a member of the M. tuberculosis complex, a group composed by species with high genetic homology. The pathogen is the etiological agent of bovine tuberculosis, an important zoonosis that is mainly transmitted by inhalation of infectious droplet nuclei or by ingestion of milk and crude milk derivative products from tuberculosis cows. The definitive identification of M. bovis
Modified evolutionary algorithm for global optimization
Institute of Scientific and Technical Information of China (English)
郭崇慧; 陆玉昌; 唐焕文
2004-01-01
A modification of evolutionary programming or evolution strategies for n-dimensional global optimization is proposed. Based on the ergodicity and inherent-randomness of chaos, the main characteristic of the new algorithm which includes two phases is that chaotic behavior is exploited to conduct a rough search of the problem space in order to find the promising individuals in Phase Ⅰ. Adjustment strategy of step-length and intensive searches in Phase Ⅱ are employed.The population sequences generated by the algorithm asymptotically converge to global optimal solutions with probability one. The proposed algorithm is applied to several typical test problems. Numerical results illustrate that this algorithm can more efficiently solve complex global optimization problems than evolutionary programming and evolution strategies in most cases.
Genetic algorithms for protein threading.
Yadgari, J; Amir, A; Unger, R
1998-01-01
Despite many years of efforts, a direct prediction of protein structure from sequence is still not possible. As a result, in the last few years researchers have started to address the "inverse folding problem": Identifying and aligning a sequence to the fold with which it is most compatible, a process known as "threading". In two meetings in which protein folding predictions were objectively evaluated, it became clear that threading as a concept promises a real breakthrough, but that much improvement is still needed in the technique itself. Threading is a NP-hard problem, and thus no general polynomial solution can be expected. Still a practical approach with demonstrated ability to find optimal solutions in many cases, and acceptable solutions in other cases, is needed. We applied the technique of Genetic Algorithms in order to significantly improve the ability of threading algorithms to find the optimal alignment of a sequence to a structure, i.e. the alignment with the minimum free energy. A major progress reported here is the design of a representation of the threading alignment as a string of fixed length. With this representation validation of alignments and genetic operators are effectively implemented. Appropriate data structure and parameters have been selected. It is shown that Genetic Algorithm threading is effective and is able to find the optimal alignment in a few test cases. Furthermore, the described algorithm is shown to perform well even without pre-definition of core elements. Existing threading methods are dependent on such constraints to make their calculations feasible. But the concept of core elements is inherently arbitrary and should be avoided if possible. While a rigorous proof is hard to submit yet an, we present indications that indeed Genetic Algorithm threading is capable of finding consistently good solutions of full alignments in search spaces of size up to 10(70).
Screening and Analysis of the Potential Bioactive Components in Rabbit Plasma after Oral Administration of Hot-Water Extracts from Leaves of <em>B>ambusa em>>textilis em>McClure
Directory of Open Access Journals (Sweden)
Jia Sun
2012-07-01
Full Text Available <em>Bambusa textilisem> McClure is a traditional Chinese medicinal plant belonging to the Bambusoideae subfamily and used to treat chronic fever and infectious diseases. To investigate the bioactive compounds absorbed in the rabbit blood after oral administration of hot-<em>water extractem>>s from em>>the leaves of em>>B. textilisem> McClure, a validated chromatographic fingerprint method was established using LC-Q-TOF-MS. Twenty compounds in bamboo leaves and three potential bioactive compounds in rabbit plasma were detected. Of the twenty detected compounds <em>in vitroem>, fifteen of which were tentatively identified either by comparing the retention time and mass spectrometry data with that of reference compounds or by reviewing the literature. Three potential bioactive compounds, including (<em>E-p>-coumaric acid, (<em>Z-p>-coumaric acid, and apigenin-8-<em>C>-β-D-(2"-<em>O>-α-L-rhamnosyl-gluco-pyranoside, were detected in both <em>the leaves of em>>B. textilis em>McClure and rabbit plasma. Of the three compounds, apigenin-8-<em>C>-β-D-(2"-<em>O>-α-L-rhamnosylglucopyranoside was identified based on its UV, MS, and NMR spectra. This study provides helpful chemical information for further pharmacology and active mechanism research on <em>B. textilisem> McClure.
Efficient Grammar Induction Algorithm with Parse Forests from Real Corpora
Kurihara, Kenichi; Kameya, Yoshitaka; Sato, Taisuke
The task of inducing grammar structures has received a great deal of attention. The reasons why researchers have studied are different; to use grammar induction as the first stage in building large treebanks or to make up better language models. However, grammar induction has inherent computational complexity. To overcome it, some grammar induction algorithms add new production rules incrementally. They refine the grammar while keeping their computational complexity low. In this paper, we propose a new efficient grammar induction algorithm. Although our algorithm is similar to algorithms which learn a grammar incrementally, our algorithm uses the graphical EM algorithm instead of the Inside-Outside algorithm. We report results of learning experiments in terms of learning speeds. The results show that our algorithm learns a grammar in constant time regardless of the size of the grammar. Since our algorithm decreases syntactic ambiguities in each step, our algorithm reduces required time for learning. This constant-time learning considerably affects learning time for larger grammars. We also reports results of evaluation of criteria to choose nonterminals. Our algorithm refines a grammar based on a nonterminal in each step. Since there can be several criteria to decide which nonterminal is the best, we evaluate them by learning experiments.
Margolis, C Z
1983-02-04
The clinical algorithm (flow chart) is a text format that is specially suited for representing a sequence of clinical decisions, for teaching clinical decision making, and for guiding patient care. A representative clinical algorithm is described in detail; five steps for writing an algorithm and seven steps for writing a set of algorithms are outlined. Five clinical education and patient care uses of algorithms are then discussed, including a map for teaching clinical decision making and protocol charts for guiding step-by-step care of specific problems. Clinical algorithms are compared as to their clinical usefulness with decision analysis. Three objections to clinical algorithms are answered, including the one that they restrict thinking. It is concluded that methods should be sought for writing clinical algorithms that represent expert consensus. A clinical algorithm could then be written for any area of medical decision making that can be standardized. Medical practice could then be taught more effectively, monitored accurately, and understood better.
Discrete extremal lengths of graph approximations of Sierpinski carpets
Malo, Robert Jason
The study of mathematical objects that are not smooth or regular has grown in importance since Benoit Mandelbrot's foundational work in the in the late 1960s. The geometry of fractals has many of its roots in that work. An important measurement of the size and structure of fractals is their dimension. We discuss various ways to describe a fractal in its canonical form. We are most interested in a concept of dimension introduced by Pierre Pansu in 1989, that of the conformal dimension. We focus on an open question: what is the conformal dimension of the Sierpinski carpet? In this work we adapt an algorithm by Oded Schramm to calculate the discrete extremal length in graph approximations of the Sierpinski carpet. We apply a result by Matias Piaggio to relate the extremal length to the Ahlfors-regular conformal dimension. We find strong numeric evidence suggesting both a lower and upper bound for this dimension.
Modified symmetrical reversible variable length code and its theoretical bounds
Tsai, Chien-Wu; Wu, Ja-Ling; Liu, Shu-Wei
2000-04-01
The reversible variable length codes (RVLCs) have been adopted in the emerging video coding standards -- H.263+ and MPEG- 4, to enhance their error-resilience capability which is important and essential in the error-prone environments. The most appealing advantage of symmetrical RVLCs compared with asymmetrical RVLCs is that only one code table is required to forward and backward decoding, however, two code tables are required for asymmetrical RVLCs. In this paper, we propose a simple and efficient algorithm that can produce a symmetrical RVLC from a given Huffman code, and we also discuss theoretical bounds of the proposed symmetrical RVLCs.
Radix-3 Algorithm for Realization of Type-II Discrete Sine Transform
Directory of Open Access Journals (Sweden)
M. N. Murty
2015-06-01
Full Text Available In this paper, radix-3 algorithm for computation of type-II discrete sine transform (DST-II of length N = 3 ( = 1,2, … . is presented. The DST-II of length N can be realized from three DST-II sequences, each of length N/3. A block diagram of for computation of the radix-3 DST-II algorithm is given. Signal flow graph for DST-II of length = 3 2 is shown to clarify the proposed algorithm.
Convolutional Encoder and Viterbi Decoder Using SOPC For Variable Constraint Length
DEFF Research Database (Denmark)
Kulkarni, Anuradha; Dnyaneshwar, Mantri; Prasad, Neeli R.;
2013-01-01
Convolution encoder and Viterbi decoder are the basic and important blocks in any Code Division Multiple Accesses (CDMA). They are widely used in communication system due to their error correcting capability But the performance degrades with variable constraint length. In this context to have...... detailed analysis, this paper deals with the implementation of convolution encoder and Viterbi decoder using system on programming chip (SOPC). It uses variable constraint length of 7, 8 and 9 bits for 1/2 and 1/3 code rates. By analyzing the Viterbi algorithm it is seen that our algorithm has a better...
Pre-defined wire length support in TopoR CAD
Directory of Open Access Journals (Sweden)
Lysenko A. A.
2009-08-01
Full Text Available This article introduces mathematical models and algorithm for calculation of wire shapes of specified length, which are inscribed in an arbitrary trapezium. This helps to save workspace, which is especially important for any-angle routing. The presented algorithm allows to maintain the defined wire length with a maximum tolerance of 50 nm. For compatibility with CAD formats that do not support arc-shaped wires, TopoR creates approximated snake-like connections made up of straight lines only.
Institute of Scientific and Technical Information of China (English)
Tian-qi WU; Min YAO; Jian-hua YANG
2016-01-01
By adopting the distributed problem-solving strategy, swarm intelligence algorithms have been successfully applied to many optimization problems that are difficult to deal with using traditional methods. At present, there are many well-implemented algorithms, such as particle swarm optimization, genetic algorithm, artificial bee colony algorithm, and ant colony optimization. These algorithms have already shown favorable performances. However, with the objects becoming increasingly complex, it is becoming gradually more difficult for these algorithms to meet human’s demand in terms of accuracy and time. Designing a new algorithm to seek better solutions for optimization problems is becoming increasingly essential. Dolphins have many noteworthy biological characteristics and living habits such as echolocation, information exchanges, cooperation, and division of labor. Combining these biological characteristics and living habits with swarm intelligence and bringing them into optimization prob-lems, we propose a brand new algorithm named the ‘dolphin swarm algorithm’ in this paper. We also provide the definitions of the algorithm and specific descriptions of the four pivotal phases in the algorithm, which are the search phase, call phase, reception phase, and predation phase. Ten benchmark functions with different properties are tested using the dolphin swarm algorithm, particle swarm optimization, genetic algorithm, and artificial bee colony algorithm. The convergence rates and benchmark func-tion results of these four algorithms are compared to testify the effect of the dolphin swarm algorithm. The results show that in most cases, the dolphin swarm algorithm performs better. The dolphin swarm algorithm possesses some great features, such as first-slow-then-fast convergence, periodic convergence, local-optimum-free, and no specific demand on benchmark functions. Moreover, the dolphin swarm algorithm is particularly appropriate to optimization problems, with more
Genotoxicity of <em>Euphorbia hirtaem>: An <em>Allium cepaem> Assay
Directory of Open Access Journals (Sweden)
Kwan Yuet Ping
2012-06-01
Full Text Available The potential genotoxic effects of methanolic extracts of <em>Euphorbia hirta em>which is commonly used in traditional medicine to treat a variety of diseased conditions including asthma, coughs, diarrhea and dysentery was investigated using <em>Allium cepaem> assay. The extracts of 125, 250, 500 and 1,000 µg/mL were tested on root meristems of <em>A. cepaem>. Ethylmethanesulfonate was used as positive control and distilled water was used as negative control. The result showed that mitotic index decreased as the concentrations of <em>E. hirtaem> extract increased. A dose-dependent increase of chromosome aberrations was also observed. Abnormalities scored were stickiness, c-mitosis, bridges and vagrant chromosomes. Micronucleated cells were also observed at interphase. Result of this study confirmed that the methanol extracts of <em>E. hirta em>exerted significant genotoxic and mitodepressive effects at 1,000 µg/mL.
Directory of Open Access Journals (Sweden)
Hye Suck An
2012-08-01
Full Text Available <em>Mytilus coruscusem> (family Mytilidae is one of the most important marine shellfish species in Korea. During the past few decades, this species has become endangered due to the loss of habitats and overfishing. Despite this species’ importance, information on its genetic background is scarce. In this study, we developed microsatellite markers for <em>M.> coruscusem> using next-generation sequencing. A total of 263,900 raw reads were obtained from a quarter-plate run on the 454 GS-FLX titanium platform, and 176,327 unique sequences were generated with an average length of 381 bp; 2569 (1.45% sequences contained a minimum of five di- to tetra-nucleotide repeat motifs. Of the 51 loci screened, 46 were amplified successfully, and 22 were polymorphic among 30 individuals, with seven of trinucleotide repeats and three of tetranucleotide repeats. All loci exhibited high genetic variability, with an average of 17.32 alleles per locus, and the mean observed and expected heterozygosities were 0.67 and 0.90, respectively. In addition, cross-amplification was tested for all 22 loci in another congener species, <em>M.> <em>galloprovincialis.> None of the primer pairs resulted in effective amplification, which might be due to their high mutation rates. Our work demonstrated the utility of next-generation 454 sequencing as a method for the rapid and cost-effective identification of microsatellites. The high degree of polymorphism exhibited by the 22 newly developed microsatellites will be useful in future conservation genetic studies of this species.
New focused crawling algorithm
Institute of Scientific and Technical Information of China (English)
Su Guiyang; Li Jianhua; Ma Yinghua; Li Shenghong; Song Juping
2005-01-01
Focused carawling is a new research approach of search engine. It restricts information retrieval and provides search service in specific topic area. Focused crawling search algorithm is a key technique of focused crawler which directly affects the search quality. This paper first introduces several traditional topic-specific crawling algorithms, then an inverse link based topic-specific crawling algorithm is put forward. Comparison experiment proves that this algorithm has a good performance in recall, obviously better than traditional Breadth-First and Shark-Search algorithms. The experiment also proves that this algorithm has a good precision.
Symplectic algebraic dynamics algorithm
Institute of Scientific and Technical Information of China (English)
2007-01-01
Based on the algebraic dynamics solution of ordinary differential equations andintegration of ,the symplectic algebraic dynamics algorithm sn is designed,which preserves the local symplectic geometric structure of a Hamiltonian systemand possesses the same precision of the na ve algebraic dynamics algorithm n.Computer experiments for the 4th order algorithms are made for five test modelsand the numerical results are compared with the conventional symplectic geometric algorithm,indicating that sn has higher precision,the algorithm-inducedphase shift of the conventional symplectic geometric algorithm can be reduced,and the dynamical fidelity can be improved by one order of magnitude.
Adaptive cockroach swarm algorithm
Obagbuwa, Ibidun C.; Abidoye, Ademola P.
2017-07-01
An adaptive cockroach swarm optimization (ACSO) algorithm is proposed in this paper to strengthen the existing cockroach swarm optimization (CSO) algorithm. The ruthless component of CSO algorithm is modified by the employment of blend crossover predator-prey evolution method which helps algorithm prevent any possible population collapse, maintain population diversity and create adaptive search in each iteration. The performance of the proposed algorithm on 16 global optimization benchmark function problems was evaluated and compared with the existing CSO, cuckoo search, differential evolution, particle swarm optimization and artificial bee colony algorithms.
Decoherence in Search Algorithms
Abal, G; Marquezino, F L; Oliveira, A C; Portugal, R
2009-01-01
Recently several quantum search algorithms based on quantum walks were proposed. Those algorithms differ from Grover's algorithm in many aspects. The goal is to find a marked vertex in a graph faster than classical algorithms. Since the implementation of those new algorithms in quantum computers or in other quantum devices is error-prone, it is important to analyze their robustness under decoherence. In this work we analyze the impact of decoherence on quantum search algorithms implemented on two-dimensional grids and on hypercubes.
Information, polarization and term length in democracy
DEFF Research Database (Denmark)
Schultz, Christian
2008-01-01
This paper considers term lengths in a representative democracy where the political issue divides the population on the left-right scale. Parties are ideologically different and better informed about the consequences of policies than voters are. A short term length makes the government more accou...... the uncertainty is large and parties are not very polarized. Partisan voters always prefer a long term length. When politicians learn while in office a long term length becomes more attractive for swing voters....
Directory of Open Access Journals (Sweden)
Jing-Lu Wang
2012-09-01
Full Text Available In the present study, antioxidant properties of flavonoids and polysaccharides from tobacco (<em>Nicotiana> tabacumem> L. leaves were evaluated in several <em>in vitroem> systems, e.g., scavenging activities on hydroxyl, superoxide anion, 1,1-diphenyl-2-picrylhydrazyl (DPPH and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid (ABTS radicals, and reducing power. Flavonoids showed much better activity than polysaccharides in scavenging activities on free radicals. When compared to the positive control, ascorbic acid, both showed weaker antioxidant potential. However, flavonoids possessed comparable superoxide anion, DPPH and ABTS radical scavenging abilities to ascorbic acid at high concentration (600 μg/mL. Meanwhile, it was found that flavonoids had prominent effects on the reducing power, which was equivalent to ascorbic acid, and was significantly higher than polysaccharides. These results clearly indicate that flavonoids are effective in scavenging free radicals and have the potential to be powerful antioxidants. Thus, tobacco leaves could be considered as a potential source of natural antioxidants for food, pharmaceutical, cosmetics or nutraceutical industries.
2010-07-01
... to an inmate hair care services which comply with applicable health and sanitation requirements. ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Hair length. 551.4 Section 551.4 Judicial... Hair length. (a) The Warden may not restrict hair length if the inmate keeps it neat and clean. (b)...
String matching with variable length gaps
DEFF Research Database (Denmark)
Bille, Philip; Gørtz, Inge Li; Vildhøj, Hjalte Wedel
2012-01-01
We consider string matching with variable length gaps. Given a string T and a pattern P consisting of strings separated by variable length gaps (arbitrary strings of length in a specified range), the problem is to find all ending positions of substrings in T that match P. This problem is a basic...
An optimal scheduling algorithm based on task duplication
Institute of Scientific and Technical Information of China (English)
Ruan Youlin; Liu Gan; Zhu Guangxi; Lu Xiaofeng
2005-01-01
When the communication time is relatively shorter than the computation time for every task, the task duplication based scheduling (TDS) algorithm proposed by Darbha and Agrawal generates an optimal schedule. Park and Choe also proposed an extended TDS algorithm whose optimality condition is less restricted than that of TDS algorithm, but the condition is very complex and is difficult to satisfy when the number of tasks is large. An efficient algorithm is proposed whose optimality condition is less restricted and simpler than both of the algorithms, and the schedule length is also shorter than both of the algorithms. The time complexity of the proposed algorithm is O ( v2 ), where v represents the number of tasks.
Modular Inverse Algorithms Without Multiplications for Cryptographic Applications
Directory of Open Access Journals (Sweden)
2006-01-01
Full Text Available Hardware and algorithmic optimization techniques are presented to the left-shift, right-shift, and the traditional Euclidean-modular inverse algorithms. Theoretical arguments and extensive simulations determined the resulting expected running time. On many computational platforms these turn out to be the fastest known algorithms for moderate operand lengths. They are based on variants of Euclidean-type extended GCD algorithms. On the considered computational platforms for operand lengths used in cryptography, the fastest presented modular inverse algorithms need about twice the time of modular multiplications, or even less. Consequently, in elliptic curve cryptography delaying modular divisions is slower (affine coordinates are the best and the RSA and ElGamal cryptosystems can be accelerated.
Modular Inverse Algorithms Without Multiplications for Cryptographic Applications
Directory of Open Access Journals (Sweden)
Laszlo Hars
2006-03-01
Full Text Available Hardware and algorithmic optimization techniques are presented to the left-shift, right-shift, and the traditional Euclidean-modular inverse algorithms. Theoretical arguments and extensive simulations determined the resulting expected running time. On many computational platforms these turn out to be the fastest known algorithms for moderate operand lengths. They are based on variants of Euclidean-type extended GCD algorithms. On the considered computational platforms for operand lengths used in cryptography, the fastest presented modular inverse algorithms need about twice the time of modular multiplications, or even less. Consequently, in elliptic curve cryptography delaying modular divisions is slower (affine coordinates are the best and the RSA and ElGamal cryptosystems can be accelerated.
Directory of Open Access Journals (Sweden)
Fernando Antonio Gonçalves
2006-08-01
Full Text Available OBJETIVO: avaliar três grandezas cefalométricas: S-N.S-Ar (ângulo sela, S-N e S-Ar, segundo a análise de Jarabak. METODOLOGIA: foram utilizadas telerradiografias cefalométricas em norma lateral de 12 indivíduos dolicofaciais com má oclusão esquelética de Classe III, sendo seis indivíduos do gênero masculino e seis do gênero feminino, com média de idade de 27,2 anos. Os resultados foram comparados com os intervalos considerados normais para cada grandeza. Para a análise estatística foi utilizado o teste t de Student, com nível de significância de 5%. RESULTADOS E CONCLUSÕES: embora os resultados não apresentassem diferenças estaticamente significantes, mostraram uma tendência de valores mais baixos que o intervalo considerado normal, para o ângulo sela e para S-N.AIM: to evaluate three cephalometric measures: S-N.S-Ar, S-N and S-Ar, according to Jarabak's analysis. METHODS: using cephalometric teleradiographies in a lateral pattern in 12 dolichofacial individuals with skeletal Class III malocclusion, being six individuals of male gender and six of female gender, having a mean age of 27,2 years. The results have been compared to the intervals considered normal for each measure. For the statistical analysis, it was used the Student's "t" test, with a significance level set on 5%. RESULTS AND CONCLUSION: although the results would have not showed statistically significant differences, S-N.S-Ar and S-N have showed a trend of more low values than the interval considered normal.
The optimal time-frequency atom search based on a modified ant colony algorithm
Institute of Scientific and Technical Information of China (English)
GUO Jun-feng; LI Yan-jun; YU Rui-xing; ZHANG Ke
2008-01-01
In this paper,a new optimal time-frequency atom search method based on a modified ant colony algorithm is proposed to improve the precision of the traditional methods.First,the discretization formula of finite length time-frequency atom is inferred at length.Second; a modified ant colony algorithm in continuous space is proposed.Finally,the optimal timefrequency atom search algorithm based on the modified ant colony algorithm is described in detail and the simulation experiment is carried on.The result indicates that the developed algorithm is valid and stable,and the precision of the method is higher than that of the traditional method.
Energy Technology Data Exchange (ETDEWEB)
Lee, Youngrok [Iowa State Univ., Ames, IA (United States)
2013-05-15
Heterogeneity exists on a data set when samples from di erent classes are merged into the data set. Finite mixture models can be used to represent a survival time distribution on heterogeneous patient group by the proportions of each class and by the survival time distribution within each class as well. The heterogeneous data set cannot be explicitly decomposed to homogeneous subgroups unless all the samples are precisely labeled by their origin classes; such impossibility of decomposition is a barrier to overcome for estimating nite mixture models. The expectation-maximization (EM) algorithm has been used to obtain maximum likelihood estimates of nite mixture models by soft-decomposition of heterogeneous samples without labels for a subset or the entire set of data. In medical surveillance databases we can find partially labeled data, that is, while not completely unlabeled there is only imprecise information about class values. In this study we propose new EM algorithms that take advantages of using such partial labels, and thus incorporate more information than traditional EM algorithms. We particularly propose four variants of the EM algorithm named EM-OCML, EM-PCML, EM-HCML and EM-CPCML, each of which assumes a specific mechanism of missing class values. We conducted a simulation study on exponential survival trees with five classes and showed that the advantages of incorporating substantial amount of partially labeled data can be highly signi cant. We also showed model selection based on AIC values fairly works to select the best proposed algorithm on each specific data set. A case study on a real-world data set of gastric cancer provided by Surveillance, Epidemiology and End Results (SEER) program showed a superiority of EM-CPCML to not only the other proposed EM algorithms but also conventional supervised, unsupervised and semi-supervised learning algorithms.
Software For Genetic Algorithms
Wang, Lui; Bayer, Steve E.
1992-01-01
SPLICER computer program is genetic-algorithm software tool used to solve search and optimization problems. Provides underlying framework and structure for building genetic-algorithm application program. Written in Think C.
Progressive geometric algorithms
Directory of Open Access Journals (Sweden)
Sander P.A. Alewijnse
2015-01-01
Full Text Available Progressive algorithms are algorithms that, on the way to computing a complete solution to the problem at hand, output intermediate solutions that approximate the complete solution increasingly well. We present a framework for analyzing such algorithms, and develop efficient progressive algorithms for two geometric problems: computing the convex hull of a planar point set, and finding popular places in a set of trajectories.
Approximate iterative algorithms
Almudevar, Anthony Louis
2014-01-01
Iterative algorithms often rely on approximate evaluation techniques, which may include statistical estimation, computer simulation or functional approximation. This volume presents methods for the study of approximate iterative algorithms, providing tools for the derivation of error bounds and convergence rates, and for the optimal design of such algorithms. Techniques of functional analysis are used to derive analytical relationships between approximation methods and convergence properties for general classes of algorithms. This work provides the necessary background in functional analysis a
Borbely, Eva
2007-01-01
A quantum algorithm is a set of instructions for a quantum computer, however, unlike algorithms in classical computer science their results cannot be guaranteed. A quantum system can undergo two types of operation, measurement and quantum state transformation, operations themselves must be unitary (reversible). Most quantum algorithms involve a series of quantum state transformations followed by a measurement. Currently very few quantum algorithms are known and no general design methodology e...
Competing Sudakov Veto Algorithms
Kleiss, Ronald
2016-01-01
We present a way to analyze the distribution produced by a Monte Carlo algorithm. We perform these analyses on several versions of the Sudakov veto algorithm, adding a cutoff, a second variable and competition between emission channels. The analysis allows us to prove that multiple, seemingly different competition algorithms, including those that are currently implemented in most parton showers, lead to the same result. Finally, we test their performance and show that there are significantly faster alternatives to the commonly used algorithms.
Autonomous Star Tracker Algorithms
DEFF Research Database (Denmark)
Betto, Maurizio; Jørgensen, John Leif; Kilsgaard, Søren
1998-01-01
Proposal, in response to an ESA R.f.P., to design algorithms for autonomous star tracker operations.The proposal also included the development of a star tracker breadboard to test the algorithms performances.......Proposal, in response to an ESA R.f.P., to design algorithms for autonomous star tracker operations.The proposal also included the development of a star tracker breadboard to test the algorithms performances....
Explaining slow convergence of EM in low noise linear mixtures
Petersen, Kaare Brandt; Winther, Ole
2005-01-01
This report conducts an investigation of the convergence properties of the EM algorithm used for linear mixture models. Since the linear mixture model is a rather general approach, the analysis is relevant for a wide range of models which to some degree are subsets of each other: Independent Component Analysis (ICA), probabilistic PCA, Factor Analysis (FA), Independent Factor Analysis (IFA) and Mean Field ICA.
A Novel Processor Scheduling Schema in Programmable Router Based on Queue Length Thresholds
Institute of Scientific and Technical Information of China (English)
Xu Ke(徐恪); Lin Chuang; Wu Jianping
2004-01-01
Programmable router may execute computing tasks except for forwarding IP packets. How to schedule the CPU in the programmable router is an important issue that needs to be solved. In this paper, the authors establish general software architecture of programmable router firstly. Based on this architecture, authors present a novel CPU scheduling algorithm based on queue length thresholds. We model this algorithm using stochastic Petri nets. The analytic results show that this scheduling algorithm can guarantee the requirements of computing of best-effort flows and QoS flows in programmable router at the same time.
Fast calculation of computer-generated hologram using run-length encoding based recurrence relation.
Nishitsuji, Takashi; Shimobaba, Tomoyoshi; Kakue, Takashi; Ito, Tomoyoshi
2015-04-20
Computer-Generated Holograms (CGHs) can be generated by superimposing zoneplates. A zoneplate is a grating that can concentrate an incident light into a point. Since a zoneplate has a circular symmetry, we reported an algorithm that rapidly generates a zoneplate by drawing concentric circles using computer graphic techniques. However, random memory access was required in the algorithm and resulted in degradation of the computational efficiency. In this study, we propose a fast CGH generation algorithm without random memory access using run-length encoding (RLE) based recurrence relation. As a result, we succeeded in improving the calculation time by 88%, compared with that of the previous work.
Directory of Open Access Journals (Sweden)
Roger Burgo de Souza
2011-03-01
Full Text Available Os objetivos do estudo foram o de mensurar o comprimento da coluna cervical quando submetida à tração manual, e o de verificar as alterações da cervical após um período de 10 sessões consecutivas. Trata-se de estudo randomizado controlado, no qual 64 participantes foram submetidos a dois procedimentos radiológicos, antes e durante a tração. As distâncias das bordas anteriores e posteriores do corpo vertebral C2 até as do corpo vertebral de C7 foram mensuradas e comparadas. Na primeira etapa as medidas das bordas anteriores foi de 8,40 para 8,50 cm (PTHE Objectives of the study were to measure the length of the cervical spine when submitted to manual traction and to verify changes in the cervical spine after 10 consecutive sessions. In this randomized controlled study 64 participants were submitted to two radiological procedures: one before and another during traction. The distances between the anterior and posterior vertebrae edges of C2 the C7 were measured and compared. In the first stage it was shown that measures of the anterior distance was 8.40 to 8.50 cm (P<0.001 and the posterior was 8.35 to 8.50 cm (P<0.001. For the second stage, subjects were randomized in control group (n=31 and intervention group (n=33 which received ten sessions of cervical traction. After the sessions the anterior and posterior distances of the intervention group increased significantly from 8.40 to 8.90 cm (P<0.001 and 8.40 to 8.65 cm (P<0.001 respectively. After the sessions all participants repeated the same radiological procedures, measurements and comparisons of the vertebral distance. When the groups were compared after the sessions there were statistically significant differences between the anterior and posterior distance of 8.20 and 8.90 cm (P=0.015 and 8.30 and 8.65 (P=0.030 respectively. Therefore the traction increased the length of the cervical spine and after a period of application of this intervention there was significant increase of
Study on BSS Algorithm used on Fault Diagnosis of Gearbox
Directory of Open Access Journals (Sweden)
Yu Chen
2013-06-01
Full Text Available The gearbox is a complicated rotating machinery equipment, in order to realize the gearbox fault early detection and prevention, it is the key to carry out the online diagnosis. This paper used the adaptive variable step-length natural gradient blind source separation algorithm to realize the helicopter gearbox meshing vibration signal and fault vibration signal effective separation. Through the algorithm simulation, the accuracy of the algorithm gained the verification and the separation error trended to zero, which has higher separation precision. This algorithm can realize the complicated mechanical vibration signal blind source separation and fault diagnosis, which has a broad application prospect.
On algorithm for building of optimal α-decision trees
Alkhalid, Abdulaziz
2010-01-01
The paper describes an algorithm that constructs approximate decision trees (α-decision trees), which are optimal relatively to one of the following complexity measures: depth, total path length or number of nodes. The algorithm uses dynamic programming and extends methods described in [4] to constructing approximate decision trees. Adjustable approximation rate allows controlling algorithm complexity. The algorithm is applied to build optimal α-decision trees for two data sets from UCI Machine Learning Repository [1]. © 2010 Springer-Verlag Berlin Heidelberg.
Heuristic algorithm for off-lattice protein folding problem
Institute of Scientific and Technical Information of China (English)
CHEN Mao; HUANG Wen-qi
2006-01-01
Enlightened by the law of interactions among objects in the physical world, we propose a heuristic algorithm for solving the three-dimensional (3D) off-lattice protein folding problem. Based on a physical model, the problem is converted from a nonlinear constraint-satisfied problem to an unconstrained optimization problem which can be solved by the well-known gradient method. To improve the efficiency of our algorithm, a strategy was introduced to generate initial configuration. Computational results showed that this algorithm could find states with lower energy than previously proposed ground states obtained by nPERM algorithm for all chains with length ranging from 13 to 55.
Husfeldt, Thore
2015-01-01
This chapter presents an introduction to graph colouring algorithms. The focus is on vertex-colouring algorithms that work for general classes of graphs with worst-case performance guarantees in a sequential model of computation. The presentation aims to demonstrate the breadth of available techniques and is organized by algorithmic paradigm.
Optimal Mixing Evolutionary Algorithms
Thierens, D.; Bosman, P.A.N.; Krasnogor, N.
2011-01-01
A key search mechanism in Evolutionary Algorithms is the mixing or juxtaposing of partial solutions present in the parent solutions. In this paper we look at the efficiency of mixing in genetic algorithms (GAs) and estimation-of-distribution algorithms (EDAs). We compute the mixing probabilities of
Implementation of Parallel Algorithms
1991-09-30
Lecture Notes in Computer Science , Warwich, England, July 16-20... Lecture Notes in Computer Science , Springer-Verlag, Bangalor, India, December 1990. J. Reif, J. Canny, and A. Page, "An Exact Algorithm for Kinodynamic...Parallel Algorithms and its Impact on Computational Geometry, in Optimal Algorithms, H. Djidjev editor, Springer-Verlag Lecture Notes in Computer Science
Semiclassical Shor's Algorithm
Giorda, P; Sen, S; Sen, S; Giorda, Paolo; Iorio, Alfredo; Sen, Samik; Sen, Siddhartha
2003-01-01
We propose a semiclassical version of Shor's quantum algorithm to factorize integer numbers, based on spin-1/2 SU(2) generalized coherent states. Surprisingly, we find numerical evidence that the algorithm's success probability is not too severely modified by our semiclassical approximation. This suggests that it is worth pursuing practical implementations of the algorithm on semiclassical devices.
Nature-inspired optimization algorithms
Yang, Xin-She
2014-01-01
Nature-Inspired Optimization Algorithms provides a systematic introduction to all major nature-inspired algorithms for optimization. The book's unified approach, balancing algorithm introduction, theoretical background and practical implementation, complements extensive literature with well-chosen case studies to illustrate how these algorithms work. Topics include particle swarm optimization, ant and bee algorithms, simulated annealing, cuckoo search, firefly algorithm, bat algorithm, flower algorithm, harmony search, algorithm analysis, constraint handling, hybrid methods, parameter tuning
A Fast Hybrid Algorithm for the Exact String Matching Problem
Directory of Open Access Journals (Sweden)
Abdulwahab A. Al-mazroi
2011-01-01
Full Text Available Problem statement: Due to huge amount and complicated nature of data being generated recently, the usage of one algorithm for string searching was not sufficient to ensure faster search and matching of patterns. So there is the urgent need to integrate two or more algorithms to form a hybrid algorithm (called BRSS to ensure speedy results. Approach: This study proposes the combination of two algorithms namely Berry-Ravindran and Skip Search Algorithms to form a hybrid algorithm in order to boost search performance. Results: The proposed hybrid algorithm contributes to better results by reducing the number of attempts, number of character comparisons and searching time. The performance of the hybrid was tested using different types of data-DNA, Protein and English text. The percentage of the improvements of the hybrid algorithm compared to Berry-Ravindran in DNA, Protein and English text are 50%, 43% and 44% respectively. The percentage of the improvements over Skip Search algorithm in DNA, Protein and English text are 20%, 30% and 18% respectively. The criteria applied for evaluation are number of attempts, number of character comparisons and searching time. Conclusion: The study shows how the integration of two algorithms gives better results than the original algorithms even the same data size and pattern lengths are applied as test evaluation on each of the algorithms.
Emergency Medical Service (EMS) Stations
Kansas Data Access and Support Center — EMS Locations in Kansas The EMS stations dataset consists of any location where emergency medical services (EMS) personnel are stationed or based out of, or where...
Length variations amongst protein domain superfamilies and consequences on structure and function.
Directory of Open Access Journals (Sweden)
Sankaran Sandhya
Full Text Available BACKGROUND: Related protein domains of a superfamily can be specified by proteins of diverse lengths. The structural and functional implications of indels in a domain scaffold have been examined. METHODOLOGY: In this study, domain superfamilies with large length variations (more than 30% difference from average domain size, referred as 'length-deviant' superfamilies and 'length-rigid' domain superfamilies (<10% length difference from average domain size were analyzed for the functional impact of such structural differences. Our delineated dataset, derived from an objective algorithm, enables us to address indel roles in the presence of peculiar structural repeats, functional variation, protein-protein interactions and to examine 'domain contexts' of proteins tolerant to large length variations. Amongst the top-10 length-deviant superfamilies analyzed, we found that 80% of length-deviant superfamilies possess distant internal structural repeats and nearly half of them acquired diverse biological functions. In general, length-deviant superfamilies have higher chance, than length-rigid superfamilies, to be engaged in internal structural repeats. We also found that approximately 40% of length-deviant domains exist as multi-domain proteins involving interactions with domains from the same or other superfamilies. Indels, in diverse domain superfamilies, were found to participate in the accretion of structural and functional features amongst related domains. With specific examples, we discuss how indels are involved directly or indirectly in the generation of oligomerization interfaces, introduction of substrate specificity, regulation of protein function and stability. CONCLUSIONS: Our data suggests a multitude of roles for indels that are specialized for domain members of different domain superfamilies. These specialist roles that we observe and trends in the extent of length variation could influence decision making in modeling of new superfamily
Directory of Open Access Journals (Sweden)
Maria Angeles Vargas
2012-09-01
Full Text Available The isolation and characterization of the lycopene ε-cyclase gene from the green microalga <em>Chlorella em>(Chromochloris> <em>zofingiensis> (<em>Czlcy-e> was performed. This gene is involved in the formation of the carotenoids α-carotene and lutein. <em>Czlcy-e> gene encoded a polypeptide of 654 amino acids. A single copy of <em>Czlcy-e> was found in <em>C. zofingiensisem>. Functional analysis by heterologous complementation in <em>Escherichia coliem> showed the ability of this protein to convert lycopene to δ-carotene. In addition, the regulation of the carotenogenic pathway by light and nitrogen was also studied in <em>C. zofingiensisem>. High irradiance stress did not increase mRNA levels of neither lycopene β<em>->cyclase gene (<em>lcy-b> nor lycopene ε-cyclase gene<em> em>(lcy-e> as compared with low irradiance conditions, whereas the transcript levels of <em>psy>, <em>pds>, <em>chyB> and <em>bkt> genes were enhanced, nevertheless triggering the synthesis of the secondary carotenoids astaxanthin, canthaxanthin and zeaxanthin and decreasing the levels of the primary carotenoids α-carotene, lutein, violaxanthin and β-carotene. Nitrogen starvation <em>per seem> enhanced mRNA levels of all genes considered, except <em>lcy-e and pdsem>, but did not trigger the synthesis of astaxanthin, canthaxanthin nor zeaxanthin. The combined effect of both high light and nitrogen starvation stresses enhanced significantly the accumulation of these carotenoids as well as the transcript levels of <em>bkt> gene, as compared with the effect of only high irradiance stress.
Estimating hull coating thickness distributions using the EM Algorithm
Corriere, Michael A.
2000-01-01
The underwater hull coating system on surface ships is comprised anti-corrosive (AC) and anti-fouling (AF) paint The AF layers are designed to wear away, continuously leaching cuprous oxide to inhibit marine growth. The thickness of the AF paint layers determines the expected service life of a coating system. Thus, it is important to assess the thickness of the AF layers to determine if the current hull coating system is sufficient. The Naval Ship Technical Manual (NSTM) provides specific gui...
Automatic detection and measurement of femur length from fetal ultrasonography
Mukherjee, Prateep; Swamy, Gokul; Gupta, Madhumita; Patil, Uday; Krishnan, Kajoli Banerjee
2010-03-01
Femur bone length is used in the assessment of fetal development and in the prediction of gestational age (GA). In this paper, we present a completely automated two-step method for identifying fetal femur and measuring its length from 2D ultrasound images. The detection algorithm uses a normalized score premised on the distribution of anatomical shape, size and presentation of the femur bone in clinically acceptable scans. The measurement process utilizes a polynomial curve fitting technique to determine the end-points of the bone from a 1D profile that is most distal from the transducer surface. The method has been tested with manual measurements made on 90 third trimester femur images by two radiologists. The measurements made by the experts are strongly correlated (Pearson's coefficient = 0.95). Likewise, the algorithm estimate is strongly correlated with expert measurements (Pearson's coefficient = 0.92 and 0.94). Based on GA estimates and their bounds specified in Standard Obstetric Tables, the GA predictions from automated measurements are found to be within +/-2SD of GA estimates from both manual measurements in 89/90 cases and within +/-3SD in all 90 cases. The method presented in this paper can be adapted to perform automatic measurement of other fetal limbs.
Beyond Mixing-length Theory: a step toward 321D
Arnett, W David; Viallet, Maxime; Campbell, Simon W; Lattanzio, John; Moćak, Miroslav
2015-01-01
We present a physical basis for algorithms to replace mixing-length theory (MLT) in stellar evolutionary computations. The 321D procedure is based on three-dimensional (3D) time-dependent solutions of the Navier-Stokes equations, including the Kolmogorov cascade as a sub-grid model of dissipation (implicit large eddy simulations; ILES). We use Reynolds-averaged Navier-Stokes (RANS) averaging to make 3D simulation data concise, and use 3D simulations to give RANS closure. We sketch a simple algorithm, which is non-local and time-dependent, with both MLT and the Lorenz convective roll as particular subsets of solutions. The damping length is determined from a balance between the large-scale driving and damping at the Kolmogorov scale. We find that (1) braking regions (boundary layers in which mixing occurs) automatically appear {\\it beyond} the edges of convection as defined by the Schwarzschild criterion, (2) dynamic (non-local) terms imply a non-zero turbulent kinetic energy flux (unlike MLT), (3) the effects...
Algorithms for Quantum Computers
Smith, Jamie
2010-01-01
This paper surveys the field of quantum computer algorithms. It gives a taste of both the breadth and the depth of the known algorithms for quantum computers, focusing on some of the more recent results. It begins with a brief review of quantum Fourier transform based algorithms, followed by quantum searching and some of its early generalizations. It continues with a more in-depth description of two more recent developments: algorithms developed in the quantum walk paradigm, followed by tensor network evaluation algorithms (which include approximating the Tutte polynomial).
Akl, Selim G
1985-01-01
Parallel Sorting Algorithms explains how to use parallel algorithms to sort a sequence of items on a variety of parallel computers. The book reviews the sorting problem, the parallel models of computation, parallel algorithms, and the lower bounds on the parallel sorting problems. The text also presents twenty different algorithms, such as linear arrays, mesh-connected computers, cube-connected computers. Another example where algorithm can be applied is on the shared-memory SIMD (single instruction stream multiple data stream) computers in which the whole sequence to be sorted can fit in the
Inheritance of telomere length in a bird.
Directory of Open Access Journals (Sweden)
Thorsten Horn
Full Text Available Telomere dynamics are intensively studied in human ageing research and epidemiology, with many correlations reported between telomere length and age-related diseases, cancer and death. While telomere length is influenced by environmental factors there is also good evidence for a strong heritable component. In human, the mode of telomere length inheritance appears to be paternal and telomere length differs between sexes, with females having longer telomeres than males. Genetic factors, e.g. sex chromosomal inactivation, and non-genetic factors, e.g. antioxidant properties of oestrogen, have been suggested as possible explanations for these sex-specific telomere inheritance and telomere length differences. To test the influence of sex chromosomes on telomere length, we investigated inheritance and sex-specificity of telomere length in a bird species, the kakapo (Strigops habroptilus, in which females are the heterogametic sex (ZW and males are the homogametic (ZZ sex. We found that, contrary to findings in humans, telomere length was maternally inherited and also longer in males. These results argue against an effect of sex hormones on telomere length and suggest that factors associated with heterogamy may play a role in telomere inheritance and sex-specific differences in telomere length.
Space vehicle Viterbi decoder. [data converters, algorithms
1975-01-01
The design and fabrication of an extremely low-power, constraint-length 7, rate 1/3 Viterbi decoder brassboard capable of operating at information rates of up to 100 kb/s is presented. The brassboard is partitioned to facilitate a later transition to an LSI version requiring even less power. The effect of soft-decision thresholds, path memory lengths, and output selection algorithms on the bit error rate is evaluated. A branch synchronization algorithm is compared with a more conventional approach. The implementation of the decoder and its test set (including all-digital noise source) are described along with the results of various system tests and evaluations. Results and recommendations are presented.
Modified Clipped LMS Algorithm
Directory of Open Access Journals (Sweden)
Lotfizad Mojtaba
2005-01-01
Full Text Available Abstract A new algorithm is proposed for updating the weights of an adaptive filter. The proposed algorithm is a modification of an existing method, namely, the clipped LMS, and uses a three-level quantization ( scheme that involves the threshold clipping of the input signals in the filter weight update formula. Mathematical analysis shows the convergence of the filter weights to the optimum Wiener filter weights. Also, it can be proved that the proposed modified clipped LMS (MCLMS algorithm has better tracking than the LMS algorithm. In addition, this algorithm has reduced computational complexity relative to the unmodified one. By using a suitable threshold, it is possible to increase the tracking capability of the MCLMS algorithm compared to the LMS algorithm, but this causes slower convergence. Computer simulations confirm the mathematical analysis presented.
Group Leaders Optimization Algorithm
Daskin, Anmer
2010-01-01
Complexity of global optimization algorithms makes implementation of the algorithms difficult and leads the algorithms to require more computer resources for the optimization process. The ability to explore the whole solution space without increasing the complexity of algorithms has a great importance to not only get reliable results but so also make the implementation of these algorithms more convenient for higher dimensional and complex-real world problems in science and engineering. In this paper, we present a new global optimization algorithm in which the influence of the leaders in social groups is used as an inspiration for the evolutionary technique that is designed into a group architecture similar to the architecture of Cooperative Coevolutionary Algorithms. Therefore, we present the implementation method and the experimental results for the single and multidimensional optimization test problems and a scientific real world problem, the energies and the geometric structures of Lennard-Jones clusters.
Entropy Message Passing Algorithm
Ilic, Velimir M; Branimir, Todorovic T
2009-01-01
Message passing over factor graph can be considered as generalization of many well known algorithms for efficient marginalization of multivariate function. A specific instance of the algorithm is obtained by choosing an appropriate commutative semiring for the range of the function to be marginalized. Some examples are Viterbi algorithm, obtained on max-product semiring and forward-backward algorithm obtained on sum-product semiring. In this paper, Entropy Message Passing algorithm (EMP) is developed. It operates over entropy semiring, previously introduced in automata theory. It is shown how EMP extends the use of message passing over factor graphs to probabilistic model algorithms such as Expectation Maximization algorithm, gradient methods and computation of model entropy, unifying the work of different authors.
Directory of Open Access Journals (Sweden)
PÉRICLES ALVES NOGUEIRA
2001-05-01
Full Text Available Introdução: A partir de 1981, a Secretaria da Saúde assumiu o tratamento e a internação de todos os casos de tuberculose no Estado de São Paulo, na região Sudeste do Brasil. Nesses anos foi observada a diminuição da incidência e da percentagem de internações por essa doença. Objetivo: Analisar a evolução dos motivos que levaram os doentes de tuberculose a internação e correlacionar esses motivos com o tempo de internação e com o tipo de alta. Material e métodos: Uma amostra de 1.805 prontuários pertencentes a cinco hospitais de tisiologia, que tratam de tuberculosos, entre os anos de 1981 e 1995 foi analisada. Resultados: O principal motivo de internação foi o mau estado geral seguido pela caquexia, tendo sido registrado o crescimento do alcoolismo. Entre os que ficaram internados menos de uma semana, destacaram-se aqueles com "outras patologias" e "insuficiência respiratória". Os motivos que levaram ao maior tempo médio de internação foram o social e a falência do tratamento. Os pacientes com insuficiência respiratória apresentaram o maior abandono e óbito. Os internados devido à intolerância medicamentosa e motivo social apresentaram maior proporção de alta a pedido; o motivo social e o alcoolismo tiveram maior taxa de alta disciplinar. O hospital que internou pacientes do sexo feminino teve o maior número de altas a pedido e os do sexo masculino se destacaram por apresentar maior freqüência de alta disciplinar e abandono.Introduction: Since 1981 the State Health Office has taken over the treatment and hospitalization of all tuberculosis cases in the State of São Paulo, southeastern Brazil. A decrease in both the incidence and the percentage of admissions due to tuberculosis has been observed during this period. Objective: To analyze the evolution of the reasons that led tuberculosis patients to hospitalization and correlate these reasons with hospitalization length and the type of discharge. Material
Institute of Scientific and Technical Information of China (English)
孙振国; 陈念; 陈强
2003-01-01
Methods of arc length control and visual image based weld detection for precision pulse TIG welding were investigated. With a particular all-hardware circuit, arc voltage during peak current stage is sampled and integrated to indicate arc length, deviation of arc length and adjusting parameters are calculated and output to drive a step motor directly. According to the features of welding image grabbed with CCD camera, a special algorithm was developed to detect the central line of weld fast and accurately. Then an application system were established, whose static arc length error is ±0.1 mm with 20 A average current and 1 mm given arc length, static detection precision of weld is 0.01 mm, processing time of each image is less than 120 ms. Precision pulse TIG welding of some given thin stainless steel components with complicated curved surface was successfully realized.
The Inverse 1-Median Problem on Tree Networks with Variable Real Edge Lengths
Directory of Open Access Journals (Sweden)
Longshu Wu
2013-01-01
Full Text Available Location problems exist in the real world and they mainly deal with finding optimal locations for facilities in a network, such as net servers, hospitals, and shopping centers. The inverse location problem is also often met in practice and has been intensively investigated in the literature. As a typical inverse location problem, the inverse 1-median problem on tree networks with variable real edge lengths is discussed in this paper, which is to modify the edge lengths at minimum total cost such that a given vertex becomes a 1-median of the tree network with respect to the new edge lengths. First, this problem is shown to be solvable in linear time with variable nonnegative edge lengths. For the case when negative edge lengths are allowable, the NP-hardness is proved under Hamming distance, and strongly polynomial time algorithms are presented under l1 and l∞ norms, respectively.
Bamatraf, Abdullah; Salleh, Mohd Najib Mohd
2011-01-01
In this paper, we introduce a new digital watermarking algorithm using least significant bit (LSB). LSB is used because of its little effect on the image. This new algorithm is using LSB by inversing the binary values of the watermark text and shifting the watermark according to the odd or even number of pixel coordinates of image before embedding the watermark. The proposed algorithm is flexible depending on the length of the watermark text. If the length of the watermark text is more than ((MxN)/8)-2 the proposed algorithm will also embed the extra of the watermark text in the second LSB. We compare our proposed algorithm with the 1-LSB algorithm and Lee's algorithm using Peak signal-to-noise ratio (PSNR). This new algorithm improved its quality of the watermarked image. We also attack the watermarked image by using cropping and adding noise and we got good results as well.
Directory of Open Access Journals (Sweden)
Marta Magi
2010-06-01
Full Text Available Abstract During 2004-2005 and 2007-2008, 189 foxes (<em>Vulpes vulpesem> and 6 badgers (<em>Meles melesem> were collected in different areas of Central Northern Italy (Piedmont, Liguria and Tuscany and examined for <em>Angiostrongylus vasorumem> infection. The prevalence of the infection was significantly different in the areas considered, with the highest values in the district of Imperia (80%, Liguria and in Montezemolo (70%, southern Piedmont; the prevalence in Tuscany was 7%. One badger collected in the area of Imperia turned out to be infected, representing the first report of the parasite in this species in Italy. Further studies are needed to evaluate the role played by fox populations as reservoirs of infection and the probability of its spreading to domestic dogs.
Riassunto <em>Angiostrongylus vasorumem> nella volpe (<em>Vulpes vulpesem> e nel tasso (<em>Meles melesem> in Italia centro-settentrionale. Nel 2004-2005 e 2007-2008, 189 volpi (<em>Vulpes vulpesem> e 6 tassi (<em>Meles melesem> provenienti da differenti aree dell'Italia settentrionale e centrale (Piemonte, Liguria Toscana, sono stati esaminati per la ricerca di <em>Angiostrongylus vasorumem>. La prevalenza del nematode è risultata significativamente diversa nelle varie zone, con valori elevati nelle zone di Imperia (80% e di Montezemolo (70%, provincia di Cuneo; la prevalenza in Toscana è risultata del 7%. Un tasso proveniente dall'area di Imperia è risultato positivo per A. vasorum; questa è la prima segnalazione del parassita in tale specie in Italia. Ulteriori studi sono necessari per valutare il potenziale della volpe come serbatoio e la possibilità di diffusione della parassitosi ai cani domestici.
doi:10.4404/hystrix-20.2-4442
Cipher for smart card using Unicode, length and position
Directory of Open Access Journals (Sweden)
Natang. A. Salgia
2011-12-01
Full Text Available Smart cards have become a common thing today. Smart cards with various utilities are used today since they are easy to carry and relatively secured. But due to advancement of technologies, smart cards are becoming increasingly insecure. A paper from certain conference suggested a new encryption algorithm to keep the information secured in smart cards and to overcome forgery attacks. It claims that, on an average, even a supercomputer will take 101084 years to decrypt, which is much higher than the previous proposals. It makes use of the length of the PIN, and the position and the Unicode value of every character in the PIN along with a secret key to create cipher text. Also, final cipher text is formed by combining two different cipher texts, one from date and time and another from PIN and secret key. And only this final cipher text is saved on the smart card making this algorithm further more secured. But few anomalies were noticed in it. Firstly, the cipher text generated using proposed formula for encryption makes securing it using position problematic. Secondly, the formula given in actual paper misses an important step, without which decryption process gives wrong output. With proposed changes these problems are eradicated and the algorithm becomes more difficult to hack.
Considerations and Algorithms for Compression of Sets
DEFF Research Database (Denmark)
Larsson, Jesper
compression algorithm that allows transparent incorporation of various estimates for probability distribution. Our experimental results allow the conclusion that set compression can benefit from incorporat- ing statistics, using our method or variants of previously known techniques.......We consider compression of unordered sets of distinct elements. After a discus- sion of the general problem, we focus on compressing sets of fixed-length bitstrings in the presence of statistical information. We survey techniques from previous work, suggesting some adjustments, and propose a novel...
Axial Globe Length in Congenital Ptosis.
Takahashi, Yasuhiro; Kang, Hyera; Kakizaki, Hirohiko
2015-01-01
To compare axial globe length between affected and unaffected sides in patients with unilateral congenital ptosis. This prospective observational study included 37 patients (age range: 7 months to 58 years). The axial globe length, margin reflex distance-1 (MRD-1), and refractive power were measured. The axial globe length difference was calculated by subtracting the axial globe length on the unaffected side from that of the affected side. The relationships among axial globe length differences, MRD-1 on the affected sides, and patient ages were analyzed using multiple regression analysis. No significant differences were found in the axial globe length between sides (P = .677). The axial globe length difference was 0.17 ± 0.30 mm (mean ± standard deviation), and two patients (5.4%), aged 32 to 57 years, showed axial globe length more than 0.67 mm longer (corresponding to a refractive power of 2 diopters) on the affected side compared to the unaffected side. The multiple regression model between axial globe length difference, patient age, and MRD-1 on the affected sides was less appropriate (YAGL = 0.003XAGE-0.048XMRD-1 +0.112; r = 0.338; adjusted r2 = 0.062; P = .127). The cylindrical power was greater on the affected side (P = .046), although the spherical power was not different between sides (P = .657). No significant difference was identified in the axial globe length between sides, and only 5% of non-pediatric patients showed an axial globe length more than 0.67 mm longer on the affected side. Congenital ptosis may have little effect on axial globe length elongation, and the risk of axial myopia-induced anisometropic amblyopia may be low in patients with unilateral congenital ptosis. Copyright 2015, SLACK Incorporated.
Diabetes mellitus and the eye: axial length
Huntjens, B.; O’Donnell, C.
2006-01-01
Background and aims: The refractive error of the eye is dependent on its axial length. Refractive error is known to fluctuate significantly in poorly controlled diabetic patients. Recently it has been reported that human eyes fluctuate in axial length during the day. However, this change is not detectable in all subjects, suggesting physiological influences such as diet. The purpose of this study was to investigate fluctuations in axial length and blood glucose levels (BGLs) in diabetic patie...
Fibonacci Lengths of Certain Nilpotent 2-Groups
Institute of Scientific and Technical Information of China (English)
H. DOOSTIE; A. T. ADNANI
2007-01-01
In this paper, we study two classes of 2-generated 2-groups of nilpotency class 2 classified by Kluempen in 2002 and also a class of finite 2-groups of high nilpotency class for their Fibonacci lengths.Their involvement in certain interesting sequences of Tribonacci numbers gives us some explicit formulas for the Fibonacci lengths and this adds to the small class of finite groups for which the Fibonacci length are known.
Large Slip Length over a Nanopatterned Surface
Institute of Scientific and Technical Information of China (English)
LI Ding; DI Qin-Feng; LI Jing-Yuan; QIAN Yue-Hong; FANG Hai-Ping
2007-01-01
A thermodynamic method is employed to analyse the slip length of hydrophobic nanopatterned surface.The maximal slip lengths with respect to the hydrophobicity of the nanopatterned surface are computed.It is found that the slip length reaches more than 50μm if the nanopatterned surfaces have a contact angle larger than 160°.Such results are expected to find extensive applications in micro-channels and helpful to understand recent experimental observations of the slippage of nanopatterned surfaces.
Dither Cavity Length Controller with Iodine Locking
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Lawson Marty
2016-01-01
Full Text Available A cavity length controller for a seeded Q-switched frequency doubled Nd:YAG laser is constructed. The cavity length controller uses a piezo-mirror dither voltage to find the optimum length for the seeded cavity. The piezo-mirror dither also dithers the optical frequency of the output pulse. [1]. This dither in optical frequency is then used to lock to an Iodine absorption line.
<em>An entem>-Kaurane-Type Diterpene in <em>Croton antisyphiliticusem> Mart.
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Ana Maria Pereira
2012-07-01
Full Text Available <em>Croton antisyphiliticus em>is a medicinal plant widely used in the treatment of microbial infections, especially those affecting the genital tract. Crude extract, fractions and pure compound isolated from roots of this species were investigated to validate their antimicrobial activity against <em>Escherichia coliem> and <em>Staphylococcus aureusem>. The compound <em>ent>-kaur-16-en-18-oic acid was isolated as a major component (0.7% of crude extract, and its MIC value determined against <em>S. aureusem> (ATCC 6538 was 250 μg/mL. This is the first phytochemical work on the species monitored with antimicrobial assay.
New length operator for loop quantum gravity
Ma, Yongge; Yang, Jinsong
2010-01-01
An alternative expression for the length operator in loop quantum gravity is presented. The operator is background-independent, symmetric, positive semi-definite, and well-defined on the kinematical Hilbert space. The expression for the regularized length operator can moreover be understood both from a simple geometrical perspective as the average of a formula relating the length to area, volume and flux operators, and also consistently as the result of direct substitution of the densitized triad operator with the functional derivative operator into the regularized expression of the length. Both these derivations are discussed, and the origin of an undetermined overall factor in each case is also elucidated.
On the attached length of orifices
Komkin, A. I.; Mironov, M. A.; Yudin, S. I.
2012-11-01
The attached length of orifices in reactive mufflers has been estimated based on numerical calculations by the finite-element method. The numerical results for a diaphragm in a duct are compared with the theoretical data obtained by Rayleigh, Fock, Karal, and Ingard. The dependence of the attached length on the diaphragm thickness is given. The results obtained are generalized for the case in which the orifice is a Helmholtz resonator neck. The effect of the resonator length on the attached length of the neck is analyzed.
Mouse gestation length is genetically determined.
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Stephen A Murray
Full Text Available BACKGROUND: Preterm birth is an enormous public health problem, affecting over 12% of live births and costing over $26 billion in the United States alone. The causes are complex, but twin studies support the role of genetics in determining gestation length. Despite widespread use of the mouse in studies of the genetics of preterm birth, there have been few studies that actually address the precise natural gestation length of the mouse, and to what degree the timing of labor and birth is genetically determined. METHODOLOGY/PRINCIPAL FINDINGS: To further develop the mouse as a genetic model of preterm birth, we developed a high-throughput monitoring system and measured the gestation length in 15 inbred strains. Our results show an unexpectedly wide variation in overall gestation length between strains that approaches two full days, while intra-strain variation is quite low. Although litter size shows a strong inverse correlation with gestation length, genetic difference alone accounts for a significant portion of the variation. In addition, ovarian transplant experiments support a primary role of maternal genetics in the determination of gestation length. Preliminary analysis of gestation length in the C57BL/6J-Chr#(A/J/NaJ chromosome substitution strain (B.A CSS panel suggests complex genetic control of gestation length. CONCLUSIONS/SIGNIFICANCE: Together, these data support the role of genetics in regulating gestation length and present the mouse as an important tool for the discovery of genes governing preterm birth.
Le, Thanh; Altman, Tom; Gardiner, Katheleen
2010-02-01
Identification of motifs in biological sequences is a challenging problem because such motifs are often short, degenerate, and may contain gaps. Most algorithms that have been developed for motif-finding use the expectation-maximization (EM) algorithm iteratively. Although EM algorithms can converge quickly, they depend strongly on initialization parameters and can converge to local sub-optimal solutions. In addition, they cannot generate gapped motifs. The effectiveness of EM algorithms in motif finding can be improved by incorporating methods that choose different sets of initial parameters to enable escape from local optima, and that allow gapped alignments within motif models. We have developed HIGEDA, an algorithm that uses the hierarchical gene-set genetic algorithm (HGA) with EM to initiate and search for the best parameters for the motif model. In addition, HIGEDA can identify gapped motifs using a position weight matrix and dynamic programming to generate an optimal gapped alignment of the motif model with sequences from the dataset. We show that HIGEDA outperforms MEME and other motif-finding algorithms on both DNA and protein sequences. Source code and test datasets are available for download at http://ouray.cudenver.edu/~tnle/, implemented in C++ and supported on Linux and MS Windows.
Kim, Ye-seul; Park, Hye-suk; Lee, Haeng-Hwa; Choi, Young-Wook; Choi, Jae-Gu; Kim, Hak Hee; Kim, Hee-Joung
2016-02-01
Digital breast tomosynthesis (DBT) is a recently developed system for three-dimensional imaging that offers the potential to reduce the false positives of mammography by preventing tissue overlap. Many qualitative evaluations of digital breast tomosynthesis were previously performed by using a phantom with an unrealistic model and with heterogeneous background and noise, which is not representative of real breasts. The purpose of the present work was to compare reconstruction algorithms for DBT by using various breast phantoms; validation was also performed by using patient images. DBT was performed by using a prototype unit that was optimized for very low exposures and rapid readout. Three algorithms were compared: a back-projection (BP) algorithm, a filtered BP (FBP) algorithm, and an iterative expectation maximization (EM) algorithm. To compare the algorithms, three types of breast phantoms (homogeneous background phantom, heterogeneous background phantom, and anthropomorphic breast phantom) were evaluated, and clinical images were also reconstructed by using the different reconstruction algorithms. The in-plane image quality was evaluated based on the line profile and the contrast-to-noise ratio (CNR), and out-of-plane artifacts were evaluated by means of the artifact spread function (ASF). Parenchymal texture features of contrast and homogeneity were computed based on reconstructed images of an anthropomorphic breast phantom. The clinical images were studied to validate the effect of reconstruction algorithms. The results showed that the CNRs of masses reconstructed by using the EM algorithm were slightly higher than those obtained by using the BP algorithm, whereas the FBP algorithm yielded much lower CNR due to its high fluctuations of background noise. The FBP algorithm provides the best conspicuity for larger calcifications by enhancing their contrast and sharpness more than the other algorithms; however, in the case of small-size and low
Focal length estimation guided with object distribution on FocaLens dataset
Yan, Han; Zhang, Yu; Zhang, Shunli; Zhao, Sicong; Zhang, Li
2017-05-01
The focal length information of an image is indispensable for many computer vision tasks. In general, focal length can be obtained via camera calibration using specific planner patterns. However, for images taken by an unknown device, focal length can only be estimated based on the image itself. Currently, most of the single-image focal length estimation methods make use of predefined geometric cues (such as vanishing points or parallel lines) to infer focal length, which constrains their applications mainly on manmade scenes. The machine learning algorithms have demonstrated great performance in many computer vision tasks, but these methods are seldom used in the focal length estimation task, partially due to the shortage of labeled images for training the model. To bridge this gap, we first introduce a large-scale dataset FocaLens, which is especially designed for single-image focal length estimation. Taking advantage of the FocaLens dataset, we also propose a new focal length estimation model, which exploits the multiscale detection architecture to encode object distributions in images to assist focal length estimation. Additionally, an online focal transformation approach is proposed to further promote the model's generalization ability. Experimental results demonstrate that the proposed model trained on FocaLens can not only achieve state-of-the-art results on the scenes with distinct geometric cues but also obtain comparable results on the scenes even without distinct geometric cues.
AN ADAPTIVE MEMBRANE ALGORITHM FOR SOLVING COMBINATORIAL OPTIMIZATION PROBLEMS
Institute of Scientific and Technical Information of China (English)
Juanjuan HE; Jianhua XIAO; Zehui SHAO
2014-01-01
Membrane algorithms (MAs), which inherit from P systems, constitute a new parallel and distribute framework for approximate computation. In the paper, a membrane algorithm is proposed with the improvement that the involved parameters can be adaptively chosen. In the algorithm, some membranes can evolve dynamically during the computing process to specify the values of the requested parameters. The new algorithm is tested on a well-known combinatorial optimization problem, the travelling salesman problem. The em-pirical evidence suggests that the proposed approach is efficient and reliable when dealing with 11 benchmark instances, particularly obtaining the best of the known solutions in eight instances. Compared with the genetic algorithm, simulated annealing algorithm, neural net-work and a fine-tuned non-adaptive membrane algorithm, our algorithm performs better than them. In practice, to design the airline network that minimize the total routing cost on the CAB data with twenty-five US cities, we can quickly obtain high quality solutions using our algorithm.
Conformational states of the full-length glucagon receptor
Yang, Linlin; Yang, Dehua; de Graaf, Chris; Moeller, Arne; West, Graham M.; Dharmarajan, Venkatasubramanian; Wang, Chong; Siu, Fai Y.; Song, Gaojie; Reedtz-Runge, Steffen; Pascal, Bruce D.; Wu, Beili; Potter, Clinton S.; Zhou, Hu; Griffin, Patrick R.; Carragher, Bridget; Yang, Huaiyu; Wang, Ming-Wei; Stevens, Raymond C.; Jiang, Hualiang
2015-07-01
Class B G protein-coupled receptors are composed of an extracellular domain (ECD) and a seven-transmembrane (7TM) domain, and their signalling is regulated by peptide hormones. Using a hybrid structural biology approach together with the ECD and 7TM domain crystal structures of the glucagon receptor (GCGR), we examine the relationship between full-length receptor conformation and peptide ligand binding. Molecular dynamics (MD) and disulfide crosslinking studies suggest that apo-GCGR can adopt both an open and closed conformation associated with extensive contacts between the ECD and 7TM domain. The electron microscopy (EM) map of the full-length GCGR shows how a monoclonal antibody stabilizes the ECD and 7TM domain in an elongated conformation. Hydrogen/deuterium exchange (HDX) studies and MD simulations indicate that an open conformation is also stabilized by peptide ligand binding. The combined studies reveal the open/closed states of GCGR and suggest that glucagon binds to GCGR by a conformational selection mechanism.
A low-power VLSI implementation for variable length decoder in MPEG-1 Layer III
Tsai, Tsung-Han; Liu, Chun-Nan; Chen, Wen-Cheng
2004-04-01
MPEG Layer III (MP3) audio coding algorithm is a widely used audio coding standard. It involves several complex coding techniques and is therefore difficult to create an efficient architecture design. The variable length decoding (VLD) e.g. Huffman decoding, is an important part of MP3, which needs great amount of search and memory access operations. In this paper a data driven variable length decoding algorithm is presented, which exploits the signal statistics of variable length codes to reduce power and a two-level table lookup method is presented. The decoder was designed based on simplicity and low-cost, low power consumption while retaining the high efficiency requirements. The total power saving is about 67%.
Clique Separator Decomposition of Hole- and Diamond-Free Graphs and Algorithmic Consequences
Brandstädt, Andreas
2011-01-01
Clique separator decomposition introduced by Tarjan and Whitesides is one of the most important graph decompositions. A graph is an {\\em atom} if it has no clique separator. A {\\em hole} is a chordless cycle with at least five vertices, and an {\\em antihole} is the complement graph of a hole. A graph is {\\em weakly chordal} if it is hole- and antihole-free. $K_4-e$ is also called {\\em diamond}. {\\em Paraglider} has five vertices four of which induce a diamond, and the fifth vertex sees exactly the two vertices of degree two in the diamond. In this paper we show that atoms of hole- and diamond-free graphs (of hole- and paraglider-free graphs, respectively) are either weakly chordal or of a very specific structure. Hole- and paraglider-free graphs are perfect graphs. The structure of their atoms leads to efficient algorithms for various problems.
Multiple Encryption-based Algorithm of Agricultural Product Trace Code
Institute of Scientific and Technical Information of China (English)
2012-01-01
To establish a sound traceability system of agricultural products and guarantee security of agricultural products,an algorithm is proposed to encrypt trace code of agricultural products.Original trace code consists of 34 digits indicating such information as place of origin,name of product,date of production and authentication.Area code is used to indicate enterprise information,the encrypted algorithm is designed because of the increasing code length,such coding algorithms as system conversion and section division are applied for the encrypted conversion of code of origin place and production date code,moreover,section identification code and authentication code are permutated and combined to produce check code.Through the multiple encryption and code length compression,34 digits are compressed to 20 on the basis of ensuring complete coding information,shorter code length and better encryption enable the public to know information about agricultural products without consulting professional database.
Adaptive Alternating Minimization Algorithms
Niesen, Urs; Wornell, Gregory
2007-01-01
The classical alternating minimization (or projection) algorithm has been successful in the context of solving optimization problems over two variables or equivalently of finding a point in the intersection of two sets. The iterative nature and simplicity of the algorithm has led to its application to many areas such as signal processing, information theory, control, and finance. A general set of sufficient conditions for the convergence and correctness of the algorithm is quite well-known when the underlying problem parameters are fixed. In many practical situations, however, the underlying problem parameters are changing over time, and the use of an adaptive algorithm is more appropriate. In this paper, we study such an adaptive version of the alternating minimization algorithm. As a main result of this paper, we provide a general set of sufficient conditions for the convergence and correctness of the adaptive algorithm. Perhaps surprisingly, these conditions seem to be the minimal ones one would expect in ...
Recursive forgetting algorithms
DEFF Research Database (Denmark)
Parkum, Jens; Poulsen, Niels Kjølstad; Holst, Jan
1992-01-01
In the first part of the paper, a general forgetting algorithm is formulated and analysed. It contains most existing forgetting schemes as special cases. Conditions are given ensuring that the basic convergence properties will hold. In the second part of the paper, the results are applied...... to a specific algorithm with selective forgetting. Here, the forgetting is non-uniform in time and space. The theoretical analysis is supported by a simulation example demonstrating the practical performance of this algorithm...
2016-06-07
REFERENCE ONLY NAVAL U~DERWATER SYSTEMS CENTER NEW LONDON LABORATORY NEW LONDON, CONNECTICUT 06320 Technical Memorandum SIMAS ADM XBT ALGORITHM ...REPORT TYPE Technical Memo 3. DATES COVERED 05-12-1984 to 05-12-1984 4. TITLE AND SUBTITLE SIMAS ADM XBT Algorithm 5a. CONTRACT NUMBER 5b...NOTES NUWC2015 14. ABSTRACT An algorithm has been developed for the detection and correction of surface ship launched expendable bathythermograph
Static Analysis Numerical Algorithms
2016-04-01
STATIC ANALYSIS OF NUMERICAL ALGORITHMS KESTREL TECHNOLOGY, LLC APRIL 2016 FINAL TECHNICAL REPORT APPROVED FOR PUBLIC RELEASE; DISTRIBUTION...3. DATES COVERED (From - To) NOV 2013 – NOV 2015 4. TITLE AND SUBTITLE STATIC ANALYSIS OF NUMERICAL ALGORITHMS 5a. CONTRACT NUMBER FA8750-14-C... algorithms , linear digital filters and integrating accumulators, modifying existing versions of Honeywell’s HiLiTE model-based development system and
Recursive forgetting algorithms
DEFF Research Database (Denmark)
Parkum, Jens; Poulsen, Niels Kjølstad; Holst, Jan
1992-01-01
In the first part of the paper, a general forgetting algorithm is formulated and analysed. It contains most existing forgetting schemes as special cases. Conditions are given ensuring that the basic convergence properties will hold. In the second part of the paper, the results are applied...... to a specific algorithm with selective forgetting. Here, the forgetting is non-uniform in time and space. The theoretical analysis is supported by a simulation example demonstrating the practical performance of this algorithm...
Fingerprint Feature Extraction Algorithm
Directory of Open Access Journals (Sweden)
Mehala. G
2014-03-01
Full Text Available The goal of this paper is to design an efficient Fingerprint Feature Extraction (FFE algorithm to extract the fingerprint features for Automatic Fingerprint Identification Systems (AFIS. FFE algorithm, consists of two major subdivisions, Fingerprint image preprocessing, Fingerprint image postprocessing. A few of the challenges presented in an earlier are, consequently addressed, in this paper. The proposed algorithm is able to enhance the fingerprint image and also extracting true minutiae.
Fingerprint Feature Extraction Algorithm
Mehala. G
2014-01-01
The goal of this paper is to design an efficient Fingerprint Feature Extraction (FFE) algorithm to extract the fingerprint features for Automatic Fingerprint Identification Systems (AFIS). FFE algorithm, consists of two major subdivisions, Fingerprint image preprocessing, Fingerprint image postprocessing. A few of the challenges presented in an earlier are, consequently addressed, in this paper. The proposed algorithm is able to enhance the fingerprint image and also extractin...
Redesigning linear algebra algorithms
Energy Technology Data Exchange (ETDEWEB)
Dongarra, J.J.
1983-01-01
Many of the standard algorithms in linear algebra as implemented in FORTRAN do not achieve maximum performance on today's large-scale vector computers. The author examines the problem and constructs alternative formulations of algorithms that do not lose the clarity of the original algorithm or sacrifice the FORTRAN portable environment, but do gain the performance attainable on these supercomputers. The resulting implementation not only performs well on vector computers but also increases performance on conventional sequential computers. 13 references.
Redesigning linear algebra algorithms
Energy Technology Data Exchange (ETDEWEB)
Dongarra, J.J.
1983-01-01
Many of the standard algorithms in linear algebra as implemented in FORTRAN do not achieve maximum performance on today's large-scale vector computers. In this paper we examine the problem and construct alternative formulations of algorithms that do not lose the clarity of the original algorithm or sacrifice the Fortran portable environment, but do gain the performance attainable on these supercomputers. The resulting implementation not only performs well on vector computers but also increases performance on conventional sequential computers.
2010-04-01
... power unit behind the cab and on an over-cab rack. No State shall impose an overall length limitation of... may carry boats on the power unit so long as the length and width restrictions of the vehicles and...) in 23 CFR 658.19. (6) Munitions carriers using dromedary equipment. A truck tractor equipped with...
Length-biased Weighted Maxwell Distribution
Directory of Open Access Journals (Sweden)
Kanak Modi
2015-12-01
Full Text Available The concept of length-biased distribution can be employed in development of proper models for life-time data. In this paper, we develop the length-biased form of Weighted Maxwell distribution (WMD. We study the statistical properties of the derived distribution including moments, moment generating function, hazard rate, reverse hazard rate, Shannon entropy and estimation of parameters
Segment lengths influence hill walking strategies.
Sheehan, Riley C; Gottschall, Jinger S
2014-08-22
Segment lengths are known to influence walking kinematics and muscle activity patterns. During level walking at the same speed, taller individuals take longer, slower strides than shorter individuals. Based on this, we sought to determine if segment lengths also influenced hill walking strategies. We hypothesized that individuals with longer segments would display more joint flexion going uphill and more extension going downhill as well as greater lateral gastrocnemius and vastus lateralis activity in both directions. Twenty young adults of varying heights (below 155 cm to above 188 cm) walked at 1.25 m/s on a level treadmill as well as 6° and 12° up and downhill slopes while we collected kinematic and muscle activity data. Subsequently, we ran linear regressions for each of the variables with height, leg, thigh, and shank length. Despite our population having twice the anthropometric variability, the level and hill walking patterns matched closely with previous studies. While there were significant differences between level and hill walking, there were few hill walking variables that were correlated with segment length. In support of our hypothesis, taller individuals had greater knee and ankle flexion during uphill walking. However, the majority of the correlations were between tibialis anterior and lateral gastrocnemius activities and shank length. Contrary to our hypothesis, relative step length and muscle activity decreased with segment length, specifically shank length. In summary, it appears that individuals with shorter segments require greater propulsion and toe clearance during uphill walking as well as greater braking and stability during downhill walking.
Influence of mandibular length on mouth opening
Dijkstra, PU; Hof, AL; Stegenga, B; De Bont, LGM
1999-01-01
Theoretically, mouth opening not only reflects the mobility of the temporomandibular joints (TMJs) but also the mandibular length. Clinically, the exact relationship between mouth opening, mandibular length, and mobility of TMJs is unclear. To study this relationship 91 healthy subjects, 59 women an
Extending electronic length frequency analysis in R
DEFF Research Database (Denmark)
Taylor, M. H.; Mildenberger, Tobias K.
2017-01-01
Electronic length frequency analysis (ELEFAN) is a system of stock assessment methods using length-frequency (LFQ) data. One step is the estimation of growth from the progression of LFQ modes through time using the von Bertalanffy growth function (VBGF). The option to fit a seasonally oscillating...
Leaf Length Variation in Perennial Forage Grasses
Directory of Open Access Journals (Sweden)
Philippe Barre
2015-08-01
Full Text Available Leaf length is a key factor in the economic value of different grass species and cultivars in forage production. It is also important for the survival of individual plants within a sward. The objective of this paper is to discuss the basis of within-species variation in leaf length. Selection for leaf length has been highly efficient, with moderate to high narrow sense heritability. Nevertheless, the genetic regulation of leaf length is complex because it involves many genes with small individual effects. This could explain the low stability of QTL found in different studies. Leaf length has a strong response to environmental conditions. However, when significant genotype × environment interactions have been identified, their effects have been smaller than the main effects. Recent modelling-based research suggests that many of the reported environmental effects on leaf length and genotype × environment interactions could be biased. Indeed, it has been shown that leaf length is an emergent property strongly affected by the architectural state of the plant during significant periods prior to leaf emergence. This approach could lead to improved understanding of the factors affecting leaf length, as well as better estimates of the main genetic effects.
Analysis of ureteral length in adult cadavers
Directory of Open Access Journals (Sweden)
Hugo F. F. Novaes
2013-04-01
Full Text Available Introduction In some occasions, correlations between human structures can help planning surgical intra-abdominal interventions. The previous determination of ureteral length helps pre-operatory planning of surgeries, reduces costs of auxiliary exams, the correct choice of double-J catheter with low morbidity and fewer symptoms, and an adequate adhesion to treatment. Objective To evaluate ureteral length in adult cadavers and to analyze its correlation with anthropometric measures. Materials and Methods: From April 2009 to January 2012 we determined ureteral length of adult cadavers submitted to necropsy and obtained the following measures: height, distance from shoulder to wrist, elbow-wrist, xiphoid appendix-umbilicus, umbilicus-pubis, xiphoid appendix-pubis and between iliac spines. We analyzed the correlations between ureteral length and those anthropometric measures. Results We dissected 115 ureters from 115 adult corpses from April 2009 to January 2012. Median ureteral length didn't vary between sexes or according to height. It was observed no correlation among ureteral length and all considered anthropometric measures in all analyzed subgroups and in general population. There were no significant differences between right and left ureteral measures. Conclusions There is no difference of ureteral length in relation to height or gender (male or female. There is no significant correlation among ureteral length and the considered anthropometric measures.
2010-01-01
... 7 Agriculture 2 2010-01-01 2010-01-01 false Length. 29.6024 Section 29.6024 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6024 Length. The linear measurement of cured tobacco leaves from...
Novel algorithm of finding good candidate pre-configuration cycles in survivable WDM mesh network
Institute of Scientific and Technical Information of China (English)
ZHAO Tai-fei; YU Hong-fang; LI Le-min
2006-01-01
We present a novel algorithm of finding cycles, called the Fast Cycles Mining Algorithm (FCMA),for effi cient p-cycle network design in WDM networks. The algorithm is also flexible in that the number and the length of cycles generated are controlled by several input parameters. The problem of wavelength assign ment on p-cycle is considered in the algorithm. This algorithm is scalable and especially suitable for surviv able WDM mesh networks. Finally, the performance of the algorithm is gauged by running on some real world network topologies.
Algorithms in Algebraic Geometry
Dickenstein, Alicia; Sommese, Andrew J
2008-01-01
In the last decade, there has been a burgeoning of activity in the design and implementation of algorithms for algebraic geometric computation. Some of these algorithms were originally designed for abstract algebraic geometry, but now are of interest for use in applications and some of these algorithms were originally designed for applications, but now are of interest for use in abstract algebraic geometry. The workshop on Algorithms in Algebraic Geometry that was held in the framework of the IMA Annual Program Year in Applications of Algebraic Geometry by the Institute for Mathematics and Its
Distributed Minimum Hop Algorithms
1982-01-01
acknowledgement), node d starts iteration i+1, and otherwise the algorithm terminates. A detailed description of the algorithm is given in pidgin algol...precise behavior of the algorithm under these circumstances is described by the pidgin algol program in the appendix which is executed by each node. The...l) < N!(2) for each neighbor j, and thus by induction,J -1 N!(2-1) < n-i + (Z-1) + N!(Z-1), completing the proof. Algorithm Dl in Pidgin Algol It is
Explaining algorithms using metaphors
Forišek, Michal
2013-01-01
There is a significant difference between designing a new algorithm, proving its correctness, and teaching it to an audience. When teaching algorithms, the teacher's main goal should be to convey the underlying ideas and to help the students form correct mental models related to the algorithm. This process can often be facilitated by using suitable metaphors. This work provides a set of novel metaphors identified and developed as suitable tools for teaching many of the 'classic textbook' algorithms taught in undergraduate courses worldwide. Each chapter provides exercises and didactic notes fo
License plate detection algorithm
Broitman, Michael; Klopovsky, Yuri; Silinskis, Normunds
2013-12-01
A novel algorithm for vehicle license plates localization is proposed. The algorithm is based on pixel intensity transition gradient analysis. Near to 2500 natural-scene gray-level vehicle images of different backgrounds and ambient illumination was tested. The best set of algorithm's parameters produces detection rate up to 0.94. Taking into account abnormal camera location during our tests and therefore geometrical distortion and troubles from trees this result could be considered as passable. Correlation between source data, such as license Plate dimensions and texture, cameras location and others, and parameters of algorithm were also defined.
Spectral Decomposition Algorithm (SDA)
National Aeronautics and Space Administration — Spectral Decomposition Algorithm (SDA) is an unsupervised feature extraction technique similar to PCA that was developed to better distinguish spectral features in...
Length contraction in Very Special Relativity
Dutta, Biplab
2011-01-01
Glashow and Cohen claim that many results of special theory of relativity (SR) like time dilation, relativistic velocity addition, etc, can be explained by using certain proper subgroups, of the Lorentz group, which collectively form the main body of Very special relativity (VSR). They did not mention about length contraction in VSR. Length contraction in VSR has not been studied at all. In this article we calculate how the length of a moving rod contracts in VSR, particularly in the HOM(2) version. The results are interesting in the sense that in general the length contraction formulas in VSR are different from SR but in many cases the two theories predict similar length contraction of moving rods.
Screening length in dusty plasma crystals
Nikolaev, V. S.; Timofeev, A. V.
2016-11-01
Particles interaction and value of the screening length in dusty plasma systems are of great interest in dusty plasma area. Three inter-particle potentials (Debye potential, Gurevich potential and interaction potential in the weakly collisional regime) are used to solve equilibrium equations for two dusty particles suspended in a parabolic trap. The inter-particle distance dependence on screening length, trap parameter and particle charge is obtained. The functional form of inter-particle distance dependence on ion temperature is investigated and compared with experimental data at 200-300 K in order to test used potentials applicability to dusty plasma systems at room temperatures. The preference is given to the Yukawa-type potential including effective values of particle charge and screening length. The estimated effective value of the screening length is 5-15 times larger than the Debye length.
Proença, Caio Carvalho; FFCH
2012-01-01
O presente ensaio pretende demonstrar reflexões sobre os usos da fotografia como fonte. Na primeira parte do ensaio procura-se demonstrar a experiência de um primeiro contato com a fonte visual, em especial a fotografia, para posteriormente entrar em contato com as diferentes formas metodológicas presente na pesquisa desta fonte. Em um segundo momento mostra-se alguns apontamentos sobre o método de pesquisa voltado à fonte visual fotográfica que auxiliam a pesquisa, contemplando a discussão s...
2015-01-01
DISPOSITIVO TÉCNICO-PEDAGÓGICO: CURSO DE METEOROLOGIA EM LINHA. Designamos por curso o sistema que resulta da relação entre um conjunto de componentes, dando unidade e identidade ao mesmo, incorporados na plataforma Versal: conjunto de 30 lições em vídeo, recursos complementares, valorização e contextualização do curso, orientação e acompanhamento desenhados e previstos, interação com os utilizadores do curso a partir do momento da sua edição aberta em linha. (https://versal.com/c/1fzwaz/m...
Szenészi, Daniela Scharamm
2005-01-01
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas. Programa de Pós-Graduação em Psicologia. Esta pesquisa objetivou investigar em atletas de triatlon a percepção das características da visualização da prova de Ironman e os seus componentes psicofisiológicos durante o transe hipnótico. Foram estudados 7 atletas do sexo masculino em 6 sessões de hipnose. Após cada sessão foi feita uma entrevista semi-estruturada e aplicado um questionário...
Rocha, Francisco José Martins
2008-01-01
Dissertação de Mestrado Integrado em Medicina Veterinária A Osteoartrite (OA) é a principal causa de claudicação no cavalo de desporto e lazer, sendo uma afecção que tem grandes repercussões económicas. Este trabalho descreve algumas das características importantes da estrutura articular, bem como da sua fisiologia. Define a OA e todas as estruturas envolvidas no seu processo. Os mecanismos fisiopatológicos põem em evidência os factores de risco em causa e que determinam tod...
Ferreira,Tânia Regina
2015-01-01
Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão, Programa de Pós-Graduação em Literatura, Florianópolis, 2015. O objetivo desta tese é fazer o estudo do desfecho do romance de Lima Barreto, Triste fim de Policarpo Quaresma - (centenário de publicação em livro 1915-2015) - adaptado para as quatro versões homônimas em quadrinhos por: Edgar Vasques e Flávio Braga (Desiderata, 2010); Cesar Lobo e Luiz Antonio Aguiar (Ática, 2010); Lailson de Holanda...
Melhores medicamentos em Pediatria
2014-01-01
Resumo: Existem actualmente muitos medicamentos que são utilizados em crianças sem terem sido suficientemente estudados nas diferentes sub-populações pediátricas, com consequências preocupantes. O reconhecimento deste facto levou à criação de regras específicas na investigação de medicamentos pediátricos nos EUA, já em 1997. De igual forma, o Regulamento de Medicamentos para Uso Pediátrico aprovado em De zembro de 2006 pelo Parlamento Europeu, tem como objectivo a resolução deste problema no ...
Approximation algorithms for curvature-constrained shortest paths
Energy Technology Data Exchange (ETDEWEB)
Wang, Hongyan; Agarwal, P.K. [Duke Univ., Durham, NC (United States)
1996-12-31
Let B be a point robot in the plane, whose path is constrained to have curvature of at most 1, and let {Omega} be a set of polygonal obstacles with n vertices. We study the collision-free, optimal path-planning problem for B. Given a parameter {epsilon}, we present an O((n{sup 2}/{epsilon}{sup 2}) log n)-time algorithm for computing a collision-free, curvature-constrained path between two given positions, whose length is at most (1 + {epsilon}) times the length of an optimal robust path (a path is robust if it remains collision-free even if certain positions on the path are perturbed). Our algorithm thus runs significantly faster than the previously best known algorithm by Jacobs and Canny whose running time is O((n+L/{epsilon}){sup 2} + n{sup 2} (n+1/{epsilon}) log n), where L is the total edge length of the obstacles. More importantly, the running time of our algorithm does not depend on the size of obstacles. The path returned by this algorithm is not necessarily robust. We present an O((n/{epsilon}){sup 2.5} log n)-time algorithm that returns a robust path whose length is at most (1 + {epsilon}) times the length of an optimal robust path. We also give a stronger characterization of curvature-constrained shortest paths, which, apart from being crucial for our algorithm, is interesting in its own right. Roughly speaking, we prove that, except in some special cases, a shortest path touches obstacles only at points that have a visible vertex nearby.
Tail paradox, partial identifiability, and influential priors in Bayesian branch length inference.
Rannala, Bruce; Zhu, Tianqi; Yang, Ziheng
2012-01-01
Recent studies have observed that Bayesian analyses of sequence data sets using the program MrBayes sometimes generate extremely large branch lengths, with posterior credibility intervals for the tree length (sum of branch lengths) excluding the maximum likelihood estimates. Suggested explanations for this phenomenon include the existence of multiple local peaks in the posterior, lack of convergence of the chain in the tail of the posterior, mixing problems, and misspecified priors on branch lengths. Here, we analyze the behavior of Bayesian Markov chain Monte Carlo algorithms when the chain is in the tail of the posterior distribution and note that all these phenomena can occur. In Bayesian phylogenetics, the likelihood function approaches a constant instead of zero when the branch lengths increase to infinity. The flat tail of the likelihood can cause poor mixing and undue influence of the prior. We suggest that the main cause of the extreme branch length estimates produced in many Bayesian analyses is the poor choice of a default prior on branch lengths in current Bayesian phylogenetic programs. The default prior in MrBayes assigns independent and identical distributions to branch lengths, imposing strong (and unreasonable) assumptions about the tree length. The problem is exacerbated by the strong correlation between the branch lengths and parameters in models of variable rates among sites or among site partitions. To resolve the problem, we suggest two multivariate priors for the branch lengths (called compound Dirichlet priors) that are fairly diffuse and demonstrate their utility in the special case of branch length estimation on a star phylogeny. Our analysis highlights the need for careful thought in the specification of high-dimensional priors in Bayesian analyses.
Effect of Calcium and Potassium on Antioxidant System of <em>Vicia fabaem> L. Under Cadmium Stress
Directory of Open Access Journals (Sweden)
Hayssam M. Ali
2012-05-01
Full Text Available Cadmium (Cd in soil poses a major threat to plant growth and productivity. In the present experiment, we studied the effect of calcium (Ca^{2+} and/or potassium (K^{+} on the antioxidant system, accumulation of proline (Pro, malondialdehyde (MDA, and content of photosynthetic pigments, cadmium (Cd and nutrients, <em>i.e.>, Ca^{2+} and K^{+} in leaf of <em>Vicia faba em>L. (cv. TARA under Cd stress. Plants grown in the presence of Cd exhibited reduced growth traits [root length (RL plant^{−1}, shoot length (SL plant^{−1}, root fresh weight (RFW plant^{−1}, shoot fresh weight (SFW plant^{−1}, root dry weight (RDW plant^{−1} and shoot dry weight (SDW plant^{−1}] and concentration of Ca^{2+}, K^{+}, Chlorophyll (Chl <em>a> and Chl <em>b em>content, except content of MDA, Cd and (Pro. The antioxidant enzymes [peroxidase (POD and superoxide dismutase (SOD] slightly increased as compared to control under Cd stress. However, a significant improvement was observed in all growth traits and content of Ca^{2+}, K^{+}, Chl <em>a>, Chl <em>b em>,Pro and activity of antioxidant enzymes catalase (CAT, POD and SOD in plants subjected to Ca^{2+} and/or K^{+}. The maximum alleviating effect was recorded in the plants grown in medium containing Ca^{2+} and K^{+} together. This study indicates that the application of Ca^{2+} and/or K^{+} had a significant and synergistic effect on plant growth. Also, application of Ca^{2+} and/or K^{+} was highly effective against the toxicity of Cd by improving activity of antioxidant enzymes and solute that led to the enhanced plant growth of faba bean plants.
Directory of Open Access Journals (Sweden)
Xiping Wang
2012-09-01
Full Text Available Powdery mildew (PM, caused by fungus <em>Erysiphe necatorem>, is one of the most devastating diseases of grapevine. To better understand grapevine-PM interaction and provide candidate resources for grapevine breeding, a suppression subtractive hybridization (SSH cDNA library was constructed from <em>E. necatorem>-infected leaves of a resistant Chinese wild <em>Vitis quinquangularisem> clone “Shang-24”. A total of 492 high quality expressed sequence tags (ESTs were obtained and assembled into 266 unigenes. Gene ontology (GO analysis indicated that 188 unigenes could be assigned with at least one GO term in the biological process category, and 176 in the molecular function category. Sequence analysis showed that a large number of these genes were homologous to those involved in defense responses. Genes involved in metabolism, photosynthesis, transport and signal transduction were also enriched in the library. Expression analysis of 13 selected genes by qRT-PCR revealed that most were induced more quickly and intensely in the resistant material “Shang-24” than in the sensitive <em>V. pseudoreticulata em>clone “Hunan-1” by<em> E. necatorem> infection. The ESTs reported here provide new clues to understand the disease-resistance mechanism in Chinese wild grapevine species and may enable us to investigate <em>E. necatorem>-responsive genes involved in PM resistance in grapevine germplasm.
AN IMPROVED OPTIMAL CHANNEL SHORTENING ALGORITHM FOR DMT MODULATION SYSTEMS
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
In Discrete Multi-Tone (DMT) modulation systems, the well-known technique to overcome the Inter-Carrier Interference (ICI)/Inter-Symbol Interference (ISI) caused by the inadequate Cyclic Prefix (CP) length is to use a Time-Domain Equalizer (TDE) at the receiver front-end. An algorithm used to calculate the coefficients of the optimal shortening Time Domain Equalizer (TDE) was given by Melsa. However, this al gorithm requires that the length of the TDE must be smaller than or equal to the memory length of the target impulse response. This paper modifies this algorithm and makes it not only fit for calculating the coefficients of the TDE with arbitrary length, but also have a much less computational time.
Kidney Length in Normal Korean Children
Energy Technology Data Exchange (ETDEWEB)
Kim, In One; Cheon, Jung Eun [Seoul National University College of Medicine, Seoul (Korea, Republic of); Lee, Young Seok [Dankook University College of Medicine, Cheonan (Korea, Republic of); Lee, Sun Wha [Ewha Womans University College of Medicine, Seoul (Korea, Republic of); Kim, Ok Hwa [Ajou University College of Medicine, Suwon (Korea, Republic of); Kim, Ji Hye [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Hong Dae [Kangnam Sacred Heart Hospital, Hanllym University College of Medicine, Seoul (Korea, Republic of); Sim, Jung Suk [Mothers Clinic, Bundang, Seongnam (Korea, Republic of)
2010-09-15
Renal length offers important information to detect or follow-up various renal diseases. The purpose of this study was to determine the kidney length of normal Korean children in relation to age, height, weight, body surface area (BSA), and body mass index (BMI). Children between 1 month and 15 years of age without urological abnormality were recruited. Children below 3rd percentile and over 97th percentile for height or weight were excluded. Both renal lengths were measured in the prone position three times and then averaged by experienced radiologists. The mean length and standard deviation for each age group was obtained, and regression equation was calculated between renal length and age, weight, height, BSA, and BMI, respectively. Renal length was measured in 550 children. Renal length grows rapidly until 24 month, while the growth rate is reduced thereafter. The regression equation for age is: renal length (mm) = 45.953 + 1.064 x age (month, {<=} 24 months) (R2 = 0.720) or 62.173 + 0.203 x age (months, > 24 months) (R2 = 0.711). The regression equation for height is: renal length (mm) = 24.494 + 0.457 x height (cm) (R2 = 0.894). The regression equation for weight is: renal length (mm) = 38.342 + 2.117 x weight (kg, {<=}18 kg) (R2 = 0.852) or 64.498 + 0.646 x weight (kg, > 18 kg) (R2 = 0.651). The regression equation for BSA is: renal length (mm) = 31.622 + 61.363 x BSA (m2, {<=} 0.7) (R2 = 0.857) or 52.717 + 29.959 x BSA (m2, > 0.7) (R2 = 0.715). The regression equation for BMI is: renal length (mm) = 44.474 + 1.163 x BMI (R2 = 0.079). This study provides data on the normal renal length and its association with age, weight, height, BSA and BMI. The results of this study will guide the detection and follow-up of renal diseases in Korean children
F[x]-lattice basis reduction algorithm and multisequence synthesis
Institute of Scientific and Technical Information of China (English)
王丽萍; 祝跃飞
2001-01-01
By means of F[x]-lattice basis reduction algorithm, a new algorithm is presented for synthesizing minimum length linear feedback shift registers (or minimal polynomials) for the given multiple sequences over a field F. Its computational complexity is O( N 2) operations in F where N is the length of each sequence. A necessary and sufficient condition for the uniqueness of minimal polynomials is given. The set and exact number of all minimal polynomials are also described when F is a finite field.
Blind Recognition Algorithm of Turbo Codes for Communication Intelligence Systems
Directory of Open Access Journals (Sweden)
Ali Naseri
2011-11-01
Full Text Available Turbo codes are widely used in land and space radio communication systems, and because of complexity of structure, are custom in military communication systems. In electronic warfare, COMINT systems make attempt to recognize codes by blind ways. In this Paper, the algorithm is proposed for blind recognition of turbo code parameters like code kind, code-word length, code rate, length of interleaver and delay blocks number of convolution code. The algorithm calculations volume is0.5L3+1.25L, therefore it is suitable for real time systems.
Directory of Open Access Journals (Sweden)
Ashraf H. F. Abd El-Wahab
2012-07-01
Full Text Available A series of naphthopyran derivatives 3a–f were prepared. Reaction of <em>2-em>amino-4-(<em>p>-chlorophenyl-7-methoxy-4<em>H>-naphtho[2,1-<em>b>]pyran-3-carbonitrile (3b with Ac_{2}O afforded two products, 2-acetylamino-7-methoxy-4-(<em>p>-chlorophenyl-4<em>H>-naphtho-[2,1-<em>b>]pyran-3-carbonitrile (4 and 10,11-dihydro-3-methoxy-9-methyl-12-(<em>p>-chloro-phenyl-12<em>H>-naphtho[2,1-<em>b>]pyran[2,3-<em>d>]pyrimidine-11-one (5 and treatment of 3b with benzoyl chloride gave the pyranopyrimidin-11-one derivative 6. While treatment of 3b with formamide afforded 11-amino-3-methoxy-12-(<em>p>-chlorophenyl-12<em>H>-naphtho[2,1-<em>b>]pyrano[2,3-<em>d>]pyrimidine (7. Reaction of 3b with triethyl orthoformate gave the corresponding 2-ethoxymethyleneamino-7-methoxy-4-(<em>p>-chlorophenyl-4<em>H>-naphtho-[2,1-<em>b>]pyran-3-carbonitrile (8. Hydrazinolysis of 8 in EtOH at room temperature yielded 10-amino-10,11-dihydro-11-imino-3-methoxy-12-(<em>p>-chlorophenyl-12<em>H>-naphtho[2,1-b]pyrano-[2,3-d]pyrimidine (9, while aminolysis of 8 with methylamine or dimethylamine gave the corresponding pyranopyrimidine and <em>N,N>-dimethylaminomethylene derivatives 10 and 11. Condensation of 9 with some carboxylic acid derivatives afforded triazolopyrimidine derivatives 12–16, while reaction of 9 with benzaldehyde gave 10-benzalamino-10,11-dihydro-11-imino-3-methoxy-12-(<em>p>-chlorophenyl12<em>H>-naphtho[2,1-<em>b>]pyrano[2,3-<em>d>]pyrimidine (17. The structures of the newly synthesized compounds were confirmed by spectral data. The
The implementation of Automatic Adaptive Equalizer Based on LMS Algorithm
Institute of Scientific and Technical Information of China (English)
2010-01-01
<正>In this paper,the inter-symbol interference and eliminating method are introduced.After analyzing the principle of adaptive equalization,we designed an adaptive equalizer using the LMS algorithm,and constructed a simulation system using MATLAB.Then we analyzed the convergence speed and mean square error characteristic of the adaptive equalizer by changing the step length factor to test the performance of the algorithm.
Improved taboo search algorithm for designing DNA sequences
Institute of Scientific and Technical Information of China (English)
Kai Zhang; Jin Xu; Xiutang Geng; Jianhua Xiao; Linqiang Pan
2008-01-01
The design of DNA sequences is one of the most practical and important research topics in DNA computing.We adopt taboo search algorithm and improve the method for the systematic design of equal-length DNA sequences,which can satisfy certain combinatorial and thermodynamic constraints.Using taboo search algorithm,our method can avoid trapping into local optimization and can find a set of good DNA sequences satisfying required constraints.
HETEROSE EM ARROZ IRRIGADO HETEROSIS IN IRRIGATED RICE
Directory of Open Access Journals (Sweden)
Elcio Perpétuo Guimarães
2007-09-01
design was a completely randomized block with three replications. Results indicate a wide genetic divergence for grain yield on the restorers lines. All hybrids showed positive heterosis for grain yield and those presenting the highest values also demonstrated positive heterosis for different yield components. These data indicate that grain yield heterosis is a result of the interaction among heterosis observed for yield components. For tillers and panicles per square meter, the positive and negative values observed were similar in number and magnitude, for the three types of heterosis studied. Panicle length and 100 grain weight were the traits that contributed the most to yield heterosis. All hybrids presented shorter growth duration than the parents. Since the parents had short stature, plant height was not significantly changed in the hybrid offspring. Hybridization increased spikelet sterility, even among cultivars within the same Indica group.
KEY-WORDS: <em>Oryza> <em>sativa>; hybrid rice; grain yield; yield components.
DEFF Research Database (Denmark)
Langhelle, Audun; Lossius, Hans Morten; Silfvast, Tom;
2004-01-01
Emergency medicine service (EMS) systems in the five Nordic countries have more similarities than differences. One similarity is the involvement of anaesthesiologists as pre-hospital physicians and their strong participation for all critically ill and injured patients in-hospital. Discrepancies do...... exist, however, especially within the ground and air ambulance service, and the EMS systems face several challenges. Main problems and challenges emphasized by the authors are: (1) Denmark: the dispatch centres are presently not under medical control and are without a national criteria based system....... Access to on-line medical advice of a physician is not available; (2) Finland: the autonomy of the individual municipalities and their responsibility to cover for primary and specialised health care, as well as the EMS, and the lack of supporting or demanding legislation regarding the EMS; (3) Iceland...
Calculating Graph Algorithms for Dominance and Shortest Path
DEFF Research Database (Denmark)
Sergey, Ilya; Midtgaard, Jan; Clarke, Dave
2012-01-01
We calculate two iterative, polynomial-time graph algorithms from the literature: a dominance algorithm and an algorithm for the single-source shortest path problem. Both algorithms are calculated directly from the definition of the properties by fixed-point fusion of (1) a least fixed point expr...... of program calculation with common practice from the school of static program analysis, and build a novel view on iterative graph algorithms as instances of abstract interpretation...... expressing all finite paths through a directed graph and (2) Galois connections that capture dominance and path length. The approach illustrates that reasoning in the style of fixed-point calculus extends gracefully to the domain of graph algorithms. We thereby bridge common practice from the school......We calculate two iterative, polynomial-time graph algorithms from the literature: a dominance algorithm and an algorithm for the single-source shortest path problem. Both algorithms are calculated directly from the definition of the properties by fixed-point fusion of (1) a least fixed point...
Optimal Merging Algorithms for Lossless Codes with Generalized Criteria
Charalambous, Themistoklis; Rezaei, Farzad
2011-01-01
This paper presents lossless prefix codes optimized with respect to a pay-off criterion consisting of a convex combination of maximum codeword length and average codeword length. The optimal codeword lengths obtained are based on a new coding algorithm which transforms the initial source probability vector into a new probability vector according to a merging rule. The coding algorithm is equivalent to a partition of the source alphabet into disjoint sets on which a new transformed probability vector is defined as a function of the initial source probability vector and a scalar parameter. The pay-off criterion considered encompasses a trade-off between maximum and average codeword length; it is related to a pay-off criterion consisting of a convex combination of average codeword length and average of an exponential function of the codeword length, and to an average codeword length pay-off criterion subject to a limited length constraint. A special case of the first related pay-off is connected to coding proble...
Directory of Open Access Journals (Sweden)
João de Almeida
2001-02-01
Full Text Available
0 presente estudo pretende analisar os significados básicos do texto "Preto e Branco", de F. Sabino, valendo-se de alguns modelos teóricos lingüísticos, principalmente de Greimas e de Pottier, em seqüência que vai da estrutura da narrativa e do percurso gerativo de sentido até as relações sêmicas, em especial.
DEFF Research Database (Denmark)
Bilardi, Gianfranco; Pietracaprina, Andrea; Pucci, Geppino
2016-01-01
A framework is proposed for the design and analysis of network-oblivious algorithms, namely algorithms that can run unchanged, yet efficiently, on a variety of machines characterized by different degrees of parallelism and communication capabilities. The framework prescribes that a network-oblivi...
2016-01-01
This project concerns the implementation of a decentralized algorithm for shape formation. The first idea was to test this algorithm with a swarm of autonomous drones but, due to the lack of time and the complexity of the project, the work was just developed in 2D and in simulation.
DEFF Research Database (Denmark)
Husfeldt, Thore
2015-01-01
This chapter presents an introduction to graph colouring algorithms. The focus is on vertex-colouring algorithms that work for general classes of graphs with worst-case performance guarantees in a sequential model of computation. The presentation aims to demonstrate the breadth of available...
Ciocanea Teodorescu I.,
2016-01-01
In this thesis we are interested in describing algorithms that answer questions arising in ring and module theory. Our focus is on deterministic polynomial-time algorithms and rings and modules that are finite. The first main result of this thesis is a solution to the module isomorphism problem in
Implementing Vehicle Routing Algorithms
1975-09-01
Multiple Depot Vehicle Dispatch Problem," presented at the URSA/TIMS meeting San Juan, Puerto Rico, Oct. 1974. 28. Gillett, B., and Miller, L., " A Heuristic Algorithm for...45. Lam, T., "Comments on a Heuristic Algorithm for the Multiple Terminal Delivery Problem," Transportation Science, Vol. 4, No. 4, Nov. 1970, p. 403
Parallel scheduling algorithms
Energy Technology Data Exchange (ETDEWEB)
Dekel, E.; Sahni, S.
1983-01-01
Parallel algorithms are given for scheduling problems such as scheduling to minimize the number of tardy jobs, job sequencing with deadlines, scheduling to minimize earliness and tardiness penalties, channel assignment, and minimizing the mean finish time. The shared memory model of parallel computers is used to obtain fast algorithms. 26 references.
Ciocanea Teodorescu I.,
2016-01-01
In this thesis we are interested in describing algorithms that answer questions arising in ring and module theory. Our focus is on deterministic polynomial-time algorithms and rings and modules that are finite. The first main result of this thesis is a solution to the module isomorphism problem in
Loo, K
2005-01-01
The goals of this paper are to show the following. First, Grover's algorithm can be viewed as a digital approximation to the analog quantum algorithm proposed in "An Analog Analogue of a Digital Quantum Computation", by E. Farhi and S. Gutmann, Phys.Rev. A 57, 2403 - 2406 (1998), quant-ph/9612026. We will call the above analog algorithm the Grover-Farhi-Gutmann or GFG algorithm. Second, the propagator of the GFG algorithm can be written as a sum-over-paths formula and given a sum-over-path interpretation, i.e., a Feynman path sum/integral. We will use nonstandard analysis to do this. Third, in the semi-classical limit $\\hbar\\to 0$, both the Grover and the GFG algorithms (viewed in the setting of the approximation in this paper) must run instantaneously. Finally, we will end the paper with an open question. In "Semiclassical Shor's Algorithm", by P. Giorda, et al, Phys. Rev.A 70, 032303 (2004), quant-ph/0303037, the authors proposed building semi-classical quantum computers to run Shor's algorithm because the ...
Improved algorithms for approximate string matching (extended abstract
Directory of Open Access Journals (Sweden)
Papamichail Georgios
2009-01-01
Full Text Available Abstract Background The problem of approximate string matching is important in many different areas such as computational biology, text processing and pattern recognition. A great effort has been made to design efficient algorithms addressing several variants of the problem, including comparison of two strings, approximate pattern identification in a string or calculation of the longest common subsequence that two strings share. Results We designed an output sensitive algorithm solving the edit distance problem between two strings of lengths n and m respectively in time O((s - |n - m|·min(m, n, s + m + n and linear space, where s is the edit distance between the two strings. This worst-case time bound sets the quadratic factor of the algorithm independent of the longest string length and improves existing theoretical bounds for this problem. The implementation of our algorithm also excels in practice, especially in cases where the two strings compared differ significantly in length. Conclusion We have provided the design, analysis and implementation of a new algorithm for calculating the edit distance of two strings with both theoretical and practical implications. Source code of our algorithm is available online.
Inproved grade length limitation of freeways
Institute of Scientific and Technical Information of China (English)
XING En-hui; PEI Yu-long
2006-01-01
A method of ascertaining grade length limitation of freeways in mountain terrain is presented. The relationship models between 15th percentile speeds and grades were built through the surveys and analyses of operation speeds on 7 typical sections of 3 freeways in mountain terrain. Using 15th percentile and 85th percentile as speed limitations, the methods of determining admitted velocities were put forward according to the grades. Deceleration distances of longitudinal slopeways were analyzed utilizing the theories of vehicle. According to the results of analysis, grade length limitation was loosed. Finally the values of grade length limitation for freeways were put forward. The results could be used as references for freeway design.
Scattering lengths of calcium and barium isotopes
Energy Technology Data Exchange (ETDEWEB)
Dammalapati, U.; Willmann, L.; Knoop, S. [Kernfysisch Versneller Instituut (KVI), University of Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands); LaserLaB Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam (Netherlands)
2011-11-15
We have calculated the s-wave scattering length of all the even isotopes of calcium (Ca) and barium (Ba) in order to investigate the prospect of Bose-Einstein condensation (BEC). For Ca we have used an accurate molecular potential based on detailed spectroscopic data. Our calculations show that Ca does not provide other isotopes alternative to the recently Bose condensed {sup 40}Ca that suffers strong losses because of a very large scattering length. For Ba we show by using a model potential that the even isotopes cover a broad range of scattering lengths, opening the possibility of BEC for at least one of the isotopes.
The tree length of an evolving coalescent
Pfaffelhuber, Peter; Weisshaupt, Heinz
2009-01-01
A well-established model for the genealogy of a large population in equilibrium is Kingman's coalescent. For the population together with its genealogy evolving in time, this gives rise to a time-stationary tree-valued process. We study the sum of the branch lengths, briefly denoted as tree length, and prove that the (suitably compensated) sequence of tree length processes converges, as the population size tends to infinity, to a limit process with cadlag paths, infinite infinitesimal variance, and a Gumbel distribution as its equilibrium.
Stylish lengths: Mate choice in flowers
Indian Academy of Sciences (India)
B T Ramesha; M D Yetish; G Ravikanth; K N Ganeshaiah; Jaboury Ghazoul; R Uma Shaanker
2011-06-01
The styles of flowers may represent an arena for pollen competition in the race to fertilize ovules. Accordingly, selection should favour a longer ‘race’ to better discriminate among variable pollen by increasing style length. Sampling across a taxonomically diverse range of wild and outcrossed species, we found that the distribution of style lengths within plants were skewed towards longer styles, as predicted. In self-pollinated domesticated species, where discrimination among pollen is less important, we found no such pattern. We conclude that style length is under directional selection towards longer styles as a mechanism for mate choice among pollen of variable quality.
Bunch Length Measurements in SPEAR3
Energy Technology Data Exchange (ETDEWEB)
Corbett, W.J.; Fisher, A.; Huang, X.; Safranek, J.; Sebek, J.; /SLAC; Lumpkin, A.; /Argonne; Sannibale, F.; /LBL, Berkeley; Mok, W.; /Unlisted
2007-11-28
A series of bunch length measurements were made in SPEAR3 for two different machine optics. In the achromatic optics the bunch length increases from the low-current value of 16.6ps rms to about 30ps at 25ma/bunch yielding an inductive impedance of -0.17{Omega}. Reducing the momentum compaction factor by a factor of {approx}60 [1] yields a low-current bunch length of {approx}4ps rms. In this paper we review the experimental setup and results.
Study on an improved five-interferogram phase-shifting algorithm
Institute of Scientific and Technical Information of China (English)
Zhiyong Luo; Jialin Dai
2008-01-01
Using traditional five-interferogram algorithm to unwrap phase for length measurement, the phase steps must be equal to π/2 exactly, but it is almost impossible to achieve in nanometer positioning technique.Aiming to overcome this defect of traditional five-interferogram algorithm, an improved five-interferogram algorithm is presented.This improved algorithm not only keeps the high accuracy of traditional five-interferogram algorithm, but also does not need absolute equal step to unwrap phase.Instead, this algorithm only needs measuring phase-shifting.With the numerical simulation, the improved five-interferogram algorithm shows high accuracy, high reliability, and feasibility in practice.It is very valuable for accurate length measurement with Fizeau interferometer and Fabry-Perot interferometer.
Energy-saving EPON Bandwidth Allocation Algorithm Supporting ONU's Sleep Mode
Zhang, Yinfa; Ren, Shuai; Liao, Xiaomin; Fang, Yuanyuan
2014-09-01
A new bandwidth allocation algorithm was presented by combining merits of the IPACT algorithm and the cyclic DBA algorithm based on the DBA algorithm for ONU's sleep mode. Simulation results indicate that compared with the normal mode ONU, the ONU's sleep mode can save about 74% of energy. The new algorithm has a smaller average packet delay and queue length in the upstream direction. While in the downstream direction, the average packet delay of the new algorithm is less than polling cycle Tcycle and the average queue length is less than the product of Tcycle and the maximum link rate. The new algorithm achieves a better compromise between energy-saving and ensuring quality of service.
Directory of Open Access Journals (Sweden)
Francesca Musiani
2013-08-01
Full Text Available Algorithms are increasingly often cited as one of the fundamental shaping devices of our daily, immersed-in-information existence. Their importance is acknowledged, their performance scrutinised in numerous contexts. Yet, a lot of what constitutes 'algorithms' beyond their broad definition as “encoded procedures for transforming input data into a desired output, based on specified calculations” (Gillespie, 2013 is often taken for granted. This article seeks to contribute to the discussion about 'what algorithms do' and in which ways they are artefacts of governance, providing two examples drawing from the internet and ICT realm: search engine queries and e-commerce websites’ recommendations to customers. The question of the relationship between algorithms and rules is likely to occupy an increasingly central role in the study and the practice of internet governance, in terms of both institutions’ regulation of algorithms, and algorithms’ regulation of our society.
DEFF Research Database (Denmark)
Bilardi, Gianfranco; Pietracaprina, Andrea; Pucci, Geppino
2016-01-01
A framework is proposed for the design and analysis of network-oblivious algorithms, namely algorithms that can run unchanged, yet efficiently, on a variety of machines characterized by different degrees of parallelism and communication capabilities. The framework prescribes that a network......-oblivious algorithm be specified on a parallel model of computation where the only parameter is the problem’s input size, and then evaluated on a model with two parameters, capturing parallelism granularity and communication latency. It is shown that for a wide class of network-oblivious algorithms, optimality...... of cache hierarchies, to the realm of parallel computation. Its effectiveness is illustrated by providing optimal network-oblivious algorithms for a number of key problems. Some limitations of the oblivious approach are also discussed....
Bayesian missing data problems EM, data augmentation and noniterative computation
Tan, Ming T; Ng, Kai Wang
2009-01-01
Bayesian Missing Data Problems: EM, Data Augmentation and Noniterative Computation presents solutions to missing data problems through explicit or noniterative sampling calculation of Bayesian posteriors. The methods are based on the inverse Bayes formulae discovered by one of the author in 1995. Applying the Bayesian approach to important real-world problems, the authors focus on exact numerical solutions, a conditional sampling approach via data augmentation, and a noniterative sampling approach via EM-type algorithms. After introducing the missing data problems, Bayesian approach, and poste
Directory of Open Access Journals (Sweden)
João Carlos Lima Rodrigues Pita
2012-08-01
Full Text Available Trachylobane-360 (<em>ent>-7α-acetoxytrachyloban-18-oic acid was isolated from <em>Xylopia langsdorffianaem>. Studies have shown that it has weak cytotoxic activity against tumor and non-tumor cells. This study investigated the <em>in vitroem>> em>and <em>in vivoem> antitumor effects of trachylobane-360, as well as its cytotoxicity in mouse erythrocytes. In order to evaluate the <em>in vivoem> toxicological aspects related to trachylobane-360 administration, hematological, biochemical and histopathological analyses of the treated animals were performed. The compound exhibited a concentration-dependent effect in inducing hemolysis with HC_{50} of 273.6 µM, and a moderate <em>in vitroem>> em>concentration-dependent inhibitory effect on the proliferation of sarcoma 180 cells with IC_{50} values of 150.8 µM and 150.4 µM, evaluated by the trypan blue exclusion test and MTT reduction assay, respectively. The <em>in vivoem> inhibition rates of sarcoma 180 tumor development were 45.60, 71.99 and 80.06% at doses of 12.5 and 25 mg/kg of trachylobane-360 and 25 mg/kg of 5-FU, respectively. Biochemical parameters were not altered. Leukopenia was observed after 5-FU treatment, but this effect was not seen with trachylobane-360 treatment. The histopathological analysis of liver and kidney showed that both organs were mildly affected by trachylobane-360 treatment. Trachylobane-360 showed no immunosuppressive effect. In conclusion, these data reinforce the anticancer potential of this natural diterpene.
A Practitioner's Guide for Variable-length Computerized Classification Testing
Directory of Open Access Journals (Sweden)
Nathan A. Thompson
2007-01-01
Full Text Available Variable-length computerized classification tests, CCTs, (Lin & Spray, 2000; Thompson, 2006 are a powerful and efficient approach to testing for the purpose of classifying examinees into groups. CCTs are designed by the specification of at least five technical components: psychometric model, calibrated item bank, starting point, item selection algorithm, and termination criterion. Several options exist for each of these CCT components, creating a myriad of possible designs. Confusion among designs is exacerbated by the lack of a standardized nomenclature. This article outlines the components of a CCT, common options for each component, and the interaction of options for different components, so that practitioners may more efficiently design CCTs. It also offers a suggestion of nomenclature.
IMPROVED ESTIMATION OF FIBER LENGTH FROM 3-DIMENSIONAL IMAGES
Directory of Open Access Journals (Sweden)
Joachim Ohser
2013-03-01
Full Text Available A new method is presented for estimating the specific fiber length from 3D images of macroscopically homogeneous fiber systems. The method is based on a discrete version of the Crofton formula, where local knowledge from 3x3x3-pixel configurations of the image data is exploited. It is shown that the relative error resulting from the discretization of the outer integral of the Crofton formula amonts at most 1.2%. An algorithmic implementation of the method is simple and the runtime as well as the amount of memory space are low. The estimation is significantly improved by considering 3x3x3-pixel configurations instead of 2x2x2, as already studied in literature.
Directory of Open Access Journals (Sweden)
Yijun Fan
2012-07-01
Full Text Available A water-soluble polysaccharide (BEBP was extracted from <em>Boletus edulis em>Bull using hot water extraction followed by ethanol precipitation. The polysaccharide BEBP was further purified by chromatography on a DEAE-cellulose column, giving three major polysaccharide fractions termed BEBP-1, BEBP-2 and BEBP-3. In the next experiment, the average molecular weight (Mw, IR and monosaccharide compositional analysis of the three polysaccharide fractions were determined. The evaluation of antioxidant activities both <em>in vitroem> and <em>in vivo em>suggested that BEBP-3 had good potential antioxidant activity, and should be explored as a novel potential antioxidant.
CPS Trawl Life History Length Frequency Data
National Oceanic and Atmospheric Administration, Department of Commerce — Length distribution of a subset of individuals from a species (mainly non-target) caught during SWFSC-FRD fishery independent trawl surveys of coastal pelagic...
A New Modified Firefly Algorithm
Directory of Open Access Journals (Sweden)
Medha Gupta
2016-07-01
Full Text Available Nature inspired meta-heuristic algorithms studies the emergent collective intelligence of groups of simple agents. Firefly Algorithm is one of the new such swarm-based metaheuristic algorithm inspired by the flashing behavior of fireflies. The algorithm was first proposed in 2008 and since then has been successfully used for solving various optimization problems. In this work, we intend to propose a new modified version of Firefly algorithm (MoFA and later its performance is compared with the standard firefly algorithm along with various other meta-heuristic algorithms. Numerical studies and results demonstrate that the proposed algorithm is superior to existing algorithms.
Cycle-by-Cycle Queue Length Estimation for Signalized Intersections Using Multi-Source Data
Institute of Scientific and Technical Information of China (English)
Zhongyu Wang; Qing Cai; Bing Wu; Yinhai Wang; Linbo Li
2015-01-01
In order to estimate vehicular queue length at signalized intersections accurately and overcome the shortcomings and restrictions of existing studies especially those based on shockwave theory, a new methodology is presented for estimating vehicular queue length using data from both point detectors and probe vehicles. The methodology applies the shockwave theory to model queue evolution over time and space. Using probe vehicle locations and times as well as point detector measured traffic states, analytical formulations for calculating the maximum and minimum ( residual) queue length are developed. The proposed methodology is verified using ground truth data collected from numerical experiments conducted in Shanghai, China. It is found that the methodology has a mean absolute percentage error of 17�09%, which is reasonably effective in estimating the queue length at traffic signalized intersections. Limitations of the proposed models and algorithms are also discussed in the paper.
Directory of Open Access Journals (Sweden)
A.M. Paci
2003-10-01
Full Text Available Lo scopo del contributo è di fornire un aggiornamento sulla presenza del Toporagno del Vallese <em>Sorex antinoriiem>, del Toporagno acquatico di Miller <em>Neomys anomalusem> e della Talpa cieca <em>Talpa caecaem> in Umbria, dove le specie risultano accertate ormai da qualche anno. A tal fine sono stati rivisitati i reperti collezionati e la bibliografia conosciuta. Toporagno del Vallese: elevato di recente a livello di specie da Brünner et al. (2002, altrimenti considerato sottospecie del Toporagno comune (<em>S. araneus antinoriiem>. È conservato uno di tre crani incompleti (mancano mandibole ed incisivi superiori al momento prudenzialmente riferiti a <em>Sorex> cfr. <em>antinorii>, provenienti dall?Appennino umbro-marchigiano settentrionale (dintorni di Scalocchio - PG, 590 m. s.l.m. e determinati sulla base della pigmentazione rossa degli ipoconi del M^{1} e M^{2}; Toporagno acquatico di Miller: tre crani (Breda in Paci e Romano op. cit. e un esemplare intero (Paci, ined. sono stati trovati a pochi chilometri di distanza gli uni dall?altro tra i comuni di Assisi e Valfabbrica, in ambienti mediocollinari limitrofi al Parco Regionale del M.te Subasio (Perugia. In provincia di Terni la specie viene segnalata da Isotti (op. cit. per i dintorni di Orvieto. Talpa cieca: sono noti una femmina e un maschio raccolti nel comune di Pietralunga (PG, rispettivamente in una conifereta a <em>Pinus nigraem> (m. 630 s.l.m. e nelle vicinanze di un bosco misto collinare a prevalenza di <em>Quercus cerrisem> (m. 640 s.l.m.. Recentemente un terzo individuo è stato rinvenuto nel comune di Sigillo (PG, all?interno del Parco Regionale di M.te Cucco, sul margine di una faggeta a 1100 m s.l.m. In entrambi i casi l?areale della specie è risultato parapatrico con quello di <em>Talpa europaeaem>.
Process for fabricating continuous lengths of superconductor
Kroeger, Donald M.; List, III, Frederick A.
1998-01-01
A process for manufacturing a superconductor. The process is accomplished by depositing a superconductor precursor powder on a continuous length of a first substrate ribbon, overlaying a continuous length of a second substrate ribbon on said first substrate ribbon, and applying sufficient pressure to form a bound layered superconductor precursor between said first substrate ribbon and said second substrates ribbon. The layered superconductor precursor is then heat treated to form a super conductor layer.