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On the median-of-k version of Hoare's selection algorithm

Rudolf Grübel
1999 RAIRO - Theoretical Informatics and Applications  
A detailed analysis of the number of comparisons for k = 1 is given in Anderson and Brown [1] , who mention a renewed interest in median-of-three sélection.  ...  these random variables, ie. on the average performance of the algorithm.  ... 
doi:10.1051/ita:1999112 fatcat:4b4nl452vffanbda3ewhgt6kgu

Range Selection and Median: Tight Cell Probe Lower Bounds and Adaptive Data Structures [chapter]

Allan Grønlund Jørgensen, Kasper Green Larsen
2011 Proceedings of the Twenty-Second Annual ACM-SIAM Symposium on Discrete Algorithms  
Range selection is the problem of preprocessing an input array A of n unique integers, such that given a query (i, j, k), one can report the k'th smallest integer in the subarray A[j].  ...  We prove cell probe lower bounds for range selection, prefix selection and range median, stating that any data structure that uses S words of space needs Ω(log n/ log(Sw/n)) time to answer a query.  ...  There exists a linear space data structure that supports range selection queries in O(log k/ log log n + log log n) time.  ... 
doi:10.1137/1.9781611973082.63 dblp:conf/soda/JorgensenL11 fatcat:f3mrcjc535cdbbqaxjfkigdhfq

A Fast Approximated k-Median Algorithm [chapter]

Eva Gómez-Ballester, Luisa Micó, Jose Oncina
2002 Lecture Notes in Computer Science  
In this paper we use this approximated median in the k-median algorithm to speed it up. ⋆ The authors thank the Spanish CICyT for partial support of this work through project  ...  Although this technique was initially defined for a vector representation of the data, the set median (the point belonging to a set P that minimizes the sum of distances to the rest of points in P ) can  ...  Acknowledgement: The authors wish to thank to Francisco Moreno-Seco for permit us the use of his synthetic data generator.  ... 
doi:10.1007/3-540-70659-3_76 fatcat:rv7uzoujmnbepg6jlflyilx32q

Practical algorithms for selection on coarse-grained parallel computers

I. Al-Furiah, S. Aluru, S. Goil, S. Ranka
1997 IEEE Transactions on Parallel and Distributed Systems  
We also consider several algorithms for load balancing needed to keep a balanced distribution of data across processors during the execution of the selection algorithms.  ...  In this paper, we consider the problem of selection on coarse-grained distributed memory parallel computers. We discuss several deterministic and randomized algorithms for parallel selection.  ...  The median of the set of these medians is found using the deterministic selection algorithm, and is used as the estimated median.  ... 
doi:10.1109/71.605768 fatcat:wdod7y3cxbcxhbtwtlm7iyn46u

A Genetic Algorithm for Solving a Capacitated p-Median Problem

Elon Santos Correa, Maria Teresinha A. Steiner, Alex A. Freitas, Celso Carnieri
2004 Numerical Algorithms  
One of the most well-known facility-location problems is the p-median problem. This work addresses an application of the capacitated p-median problem to a real-world problem.  ...  We propose a genetic algorithm (GA) to solve the capacitated pmedian problem.  ...  minimizing the costs of the admission exam (which suggests selecting a smaller number of medians).  ... 
doi:10.1023/b:numa.0000021767.42899.31 fatcat:ha4nwkkzijhl7cpfa2tbowbifm

Comparison of Four Initialization Techniques for the K-Medians Clustering Algorithm [chapter]

A. Juan, E. Vidal
2000 Lecture Notes in Computer Science  
Results clearly show the importance of a good initialization of the k-medians algorithm in all the cases.  ...  It consists of a variant of the popular k-means algorithm in which cluster medians (most centered cluster points) are used instead of the conventional cluster means.  ...  The error rate of a nearest neighbour classifier based on the prototypes selected by the k-medians algorithm will heavily depend on the value of k used.  ... 
doi:10.1007/3-540-44522-6_87 fatcat:kpmjmithijaxtb6qw6gcl7iaxq

Selection Algorithms with Small Groups [article]

Ke Chen, Adrian Dumitrescu
2019 arXiv   pre-print
We revisit the selection problem, namely that of computing the $i$th order statistic of $n$ given elements, in particular the classic deterministic algorithm by grouping and partition due to Blum, Floyd  ...  To this end we introduce three simple variants of the classic algorithm, the repeated step algorithm, the shifting target algorithm, and the hyperpair algorithm, all running in linear time.  ...  By finding the median of medians of medians instead of the median of medians, the cost of selecting the pivot m reduces from T (n/3) + O(n) to T (n/9) + O(n).  ... 
arXiv:1409.3600v3 fatcat:zdrsl46hvrg6dlucytzihv4eoi

IMPROVED NEGATIVE SELECTION BASED DECISION BASED MEDIAN FILTER FOR NOISE REMOVAL

Sarmandeep Kaur, Navneet Bawa
2015 INTERNATIONAL JOURNAL OF COMPUTERS & TECHNOLOGY  
The proposed technique seems to be effective as it will replace the noisy pixel with its best suitable alternative which is evaluated using negative selection based algorithm.  ...  The comparative analysis has clearly shown that the proposed technique outperforms over the available techniques.  ...  NEGATIVE SELECTION ALGORITHM The negative selection algorithm (NSA) is one of models in artificial immune systems. . It is based on the discriminatory mechanism of the natural system.  ... 
doi:10.24297/ijct.v14i8.1863 fatcat:ydhtywab75byxahvav2jrwhe5y

Quicksort with median of medians is considered practical [article]

Noriyuki Kurosawa
2016 arXiv   pre-print
The linear pivot selection algorithm, known as median-of-medians, makes the worst case complexity of quicksort be $\mathrm{O}(n\ln n)$.  ...  In this article, we show that we can make the quicksort with this kind of pivot selection approach be efficient.  ...  This is the use of median-of-medians or Blum-Floyd-Pratt-Rivest-Tarjan (BFPRT) algorithm -the pivot selection algorithm in the linear median finding algorithm [6] .  ... 
arXiv:1608.04852v1 fatcat:wdkcxfhxnbeg7esvl5h5zyqwxu

A Robust Median-based Background Updating Algorithm

James Ben Hayfron-Acquah
2017 International Journal of Image Graphics and Signal Processing  
This paper proposes a median based background updating algorithm which determines the median of a buffer containing values that are highly correlated.  ...  The use of cameras also make it possible for human analysis of video streams or images where it is difficult for robots or algorithms or machines to effectively deal with the images.  ...  Another disadvantage of the median-based is its method used to select the median for the updating of the background.  ... 
doi:10.5815/ijigsp.2017.02.01 fatcat:bzy2262uvbbfhiqn5qhsrzkbga

AN FPGA IMPLEMENTATION OF MODIFIED DECISION BASED UNSYMMETRICAL TRIMMED MEDIAN FILTER FOR THE REMOVAL OF SALT AND PEPPER NOISE IN DIGITAL IMAGES

CHAITANYA BETHINA, M. PREMKUMAR
2014 International Journal of Electronics Signals and Systems  
When all the pixel values are 0's and 255's then the noise pixel is replaced by mean value of all the elements present in the selected window.  ...  The proposed algorithm replaces the noisy pixel by trimmed median.  ...  Case ii): If the selected window contains not all elements as 0's and 255's. Then eliminate 255's and 0's and find the median value of the remaining elements. Replace Pij with the median value.  ... 
doi:10.47893/ijess.2014.1159 fatcat:w5e5pv7d6rgefjtly6v3y5bhse

Efficient median based clustering and classification techniques for protein sequences

P. A. Vijaya, M. Narasimha Murty, D. K. Subramanian
2006 Pattern Analysis and Applications  
It is like selecting a subset of features for sequence data sets. The experimental results of the proposed method on K-medians, SKM and Nearest  ...  In this paper, an efficient K-medians clustering (unsupervised) algorithm for prototype selection and Supervised K-medians (SKM) classification technique for protein sequences are presented.  ...  Acknowledgments We thank the anonymous reviewers for their thoughtful comments and constructive suggestions, which helped to improve the quality of this paper.  ... 
doi:10.1007/s10044-006-0040-z fatcat:rpsobezpijgijp43b2hpg57lcy

An approximate median search algorithm in non-metric spaces

Luisa Micó, Jose Oncina
2001 Pattern Recognition Letters  
In this paper a very fast algorithm (linear in time) is presented that ®nds a point that is a very good approximation of the exact median.  ...  This algorithm is independent of the distance function and does not degrade as the dimensionality of the data increases. Ó  ...  The authors thank the Spanish CICyT for partial support of this work through project CICYT TIC97-0941.  ... 
doi:10.1016/s0167-8655(01)00062-9 fatcat:qgdrxymxsnhjjnm3n7vjjkmxvi

An Efficient Hybrid CS and K-Means Algorithm for the Capacitated PMedian Problem [article]

Hassan Gholami Mazinan, Gholam Reza Ahmadi, Erfan Khaji
2014 arXiv   pre-print
Capacitated p-median problem (CPMP) is an important variation of facility location problem in which p capacitated medians are economically selected to serve a set of demand vertices so that the total assigned  ...  demand to each of the candidate medians must not exceed its capacity.  ...  Constraint (4) ensures that always p medians are selected, and constraint (5) imposes that the sum of demands assigned to a median does not exceed its capacity.  ... 
arXiv:1406.7473v1 fatcat:ys5gkfsjzrahpmv45udvtqpbky

Proposed De-noising Algorithm

Nawafil Abdulwahab Ali, Imad Al Shaikhli
2020 International Journal on Perceptive and Cognitive Computing  
The algorithm did that by selecting a window measuring 3x3 as the center of processing pixels, other algorithms did that by using median filter (MF), adopted median filter (AMF), adopted weighted filter  ...  (AWF), and the adopted weighted median filter (AWMF).  ...  The simple version of the SMF was adapted and modified for the proposed algorithm First, a standard color image was selected, then a 3x3 window was created, and the center pixel affixed as the processed  ... 
doi:10.31436/ijpcc.v6i2.164 fatcat:rrzdee4qgrfzdfzshqd46s6j74
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