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Neural gas

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682:-like learning rule", only, unlike the neural gas, it has no parameters that change over time and it is capable of continuous learning, i.e. learning on data streams. GNG has been widely used in several domains, demonstrating its capabilities for clustering data incrementally. The GNG is initialized with two randomly positioned nodes which are initially connected with a zero age edge and whose errors are set to 0. Since the in the GNG input data is presented sequentially one by one, the following steps are followed at each iteration: 669:
A number of variants of the neural gas algorithm exists in the literature so as to mitigate some of its shortcomings. More notable is perhaps Bernd Fritzke's growing neural gas, but also one should mention further elaborations such as the Growing When Required network and also the incremental growing
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Having a network with a growing set of nodes, like the one implemented by the GNG algorithm was seen as a great advantage, however some limitation on the learning was seen by the introduction of the parameter λ, in which the network would only be able to grow when iterations were a multiple of this
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Compared to self-organized map, the neural gas model does not assume that some vectors are neighbors. If two vectors happen to be close together, they would tend to move together, and if two vectors happen to be apart, they would tend to not move together. In contrast, in an SOM, if two vectors are
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If the current iteration is an integer multiple of a predefined frequency-creation threshold, a new node is inserted between the node with the largest error (among all) and its topological neighbor presenting the highest error. The link between the former and the latter nodes is eliminated (their
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parameter. The proposal to mitigate this problem was a new algorithm, the Growing When Required network (GWR), which would have the network grow more quickly, by adding nodes as quickly as possible whenever the network identified that the existing nodes would not describe the input well enough.
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The ability to only grow a network may quickly introduce overfitting; on the other hand, removing nodes on the basis of age only, as in the GNG model, does not ensure that the removed nodes are actually useless, because removal depends on a model parameter that should be carefully tuned to the
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Another neural gas variant inspired in the GNG algorithm is the incremental growing neural gas (IGNG). The authors propose the main advantage of this algorithm to be "learning new data (plasticity) without degrading the previously trained network and forgetting the old input data (stability)."
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of the feature vectors, the neural gas algorithm involves sorting, which is a procedure that does not lend itself easily to parallelization or implementation in analog hardware. However, implementations in both parallel software and analog hardware were actually designed.
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The "Plastic Neural Gas" model solves this problem by making decisions to add or remove nodes using an unsupervised version of cross-validation, which controls an equivalent notion of "generalization ability" for the unsupervised setting.
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If the stopping criterion is not met, the algorithm takes a following input. The criterion might be a given number of epochs, i.e., a pre-set number of times where all data is presented, or the reach of a maximum number of
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errors are decreased by a given factor) and the new node is connected to both of them. The error of the new node is initialized as the updated error of the node which had the largest error (among all).
49:. The algorithm was coined "neural gas" because of the dynamics of the feature vectors during the adaptation process, which distribute themselves like a gas within the data space. It is applied where 942:
Progress in pattern recognition, image analysis and applications: 12th Iberoamerican Congress on Pattern Recognition, CIARP 2007, Viña del Mar-Valparaiso, Chile, November 13–16, 2007; proceedings
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T. Martinetz, S. Berkovich, and K. Schulten. "Neural-gas" Network for Vector Quantization and its Application to Time-Series Prediction. IEEE-Transactions on Neural Networks, 4(4):558–569, 1993.
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The name "neural gas" is because one can imagine it to be what an SOM would be like if there is no underlying graph, and all points are free to move without the bonds that bind them together.
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Iqbal, Hafsa; Campo, Damian; Baydoun, Mohamad; Marcenaro, Lucio; Martin, David; Regazzoni, Carlo (2019). "Clustering Optimization for Abnormality Detection in Semi-Autonomous Systems".
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MICAI 2000: Advances in artificial intelligence : Mexican International Conference on Artificial Intelligence, Acapulco, Mexico, April 2000 : proceedings
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neighbors in the underlying graph, then they will always tend to move together, no matter whether the two vectors happen to be neighbors in the Euclidean space.
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The winner node and its topological neighbors (connected by an edge) are moving towards the current input by different fractions of their respective errors.
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Angelopoulou, Anastassia; Psarrou, Alexandra; Garcia Rodriguez, Jose; Revett, Kenneth (2005). "Computer Vision for Biomedical Image Applications". In
645:. By adapting not only the closest feature vector but all of them with a step size decreasing with increasing distance order, compared to (online) 649:
a much more robust convergence of the algorithm can be achieved. The neural gas model does not delete a node and also does not create new nodes.
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Computer vision for biomedical image applications: first international workshop, CVBIA 2005, Beijing, China, October 21, 2005 : proceedings
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Fernando Canales; Max Chacon (2007). "Progress in Pattern Recognition, Image Analysis and Applications". In Luis Rueda; Domingo Mery (eds.).
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If the winner node and the second-winner are connected by an edge, such an edge is set to 0. Else, an edge is created between them.
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Fritzke describes the growing neural gas (GNG) as an incremental network model that learns topological relations by using a "
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Marsland, Stephen; Shapiro, Jonathan; Nehmzow, Ulrich (2002). "A self-organising network that grows when required".
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If there are edges with an age larger than a threshold, they are removed. Nodes without connections are eliminated.
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Ridella, Sandro; Rovetta, Stefano; Zunino, Rodolfo (1998). "Plastic algorithm for adaptive vector quantisation".
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neural gas. A performance-oriented approach that avoids the risk of overfitting is the Plastic Neural gas model.
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Ancona, Fabio; Rovetta, Stefano; Zunino, Rodolfo (1997). "Hardware implementation of the neural gas".
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Ancona, Fabio; Rovetta, Stefano; Zunino, Rodolfo (1996). "A parallel approach to plastic neural gas".
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Prudent, Yann; Ennaji, Abdellatif (2005). "An incremental growing neural gas learns topologies".
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It is calculated the errors (distances) between the two closest nodes to the current input data.
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1st International Workshop on Multimodal Understanding and Learning for Embodied Applications
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Unsupervised Neural Networks (including Self-organizing map) in Java with source codes.
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The error of the winner node (only the closest one) is respectively accumulated.
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Proceedings. 2005 IEEE International Joint Conference on Neural Networks, 2005
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scenario, the ability to grow and shrink is suited to the more general
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Martinetz, T.; Schulten, K. (1994). "Topology representing networks".
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Proceedings of International Conference on Neural Networks (ICNN'97)
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Proceedings of International Conference on Neural Networks (ICNN'96)
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The accumulated error of all nodes is decreased by a given factor.
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The age of all edges connected to the winner node are incremented.
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Javascript simulator for Neural Gas (and other network models)
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so that the algorithm converges after many adaptation steps.
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The adaptation step of the neural gas can be interpreted as
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the index of the second closest feature vector, and so on.
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Mayora-Iberra (2000). 1314: 1296:Java Competitive Learning Applications 1098: 1096: 652: 734: 673: 1054: 1052: 1006: 1004: 973: 971: 1105:Neural Computing & Applications 1093: 1063:. Vol. 2. pp. 1211–1216. 13: 1252: 758: 14: 1333: 1283: 1218:. Vol. 2. pp. 991–994. 1177:. Vol. 1. pp. 126–130. 1049: 1001: 968: 1207: 1166: 1131: 933: 896: 865: 839: 717:Incremental growing neural gas 486: 455: 362:Update each feature vector by: 267: 261: 104: 98: 1: 1035:10.1016/s0893-6080(02)00078-3 832: 282:Compute the distance between 198:{\displaystyle i=1,\cdots ,N} 1276:10.1016/0893-6080(94)90109-0 951:10.1007/978-3-540-76725-1_71 614:are reduced with increasing 587:{\displaystyle \varepsilon } 547:{\displaystyle \varepsilon } 80: 7: 664: 574:as the neighborhood range. 85:Suppose we want to model a 10: 1338: 1322:Artificial neural networks 1069:10.1109/IJCNN.2005.1556026 855:Artificial Neural Networks 37:and introduced in 1991 by 18: 882:. Springer. p. 109. 137:using a finite number of 57:is an issue, for example 31:artificial neural network 16:Artificial neural network 1224:10.1109/ICNN.1997.616161 1183:10.1109/ICNN.1996.548878 607:{\displaystyle \lambda } 567:{\displaystyle \lambda } 87:probability distribution 19:Not to be confused with 1149:10.1145/3347450.3357657 978:Fritzke, Bernd (1995). 822: 628: 608: 588: 568: 548: 523: 353: 326: 296: 274: 245: 223: 199: 161: 131: 111: 823: 726:Growing when required 629: 609: 589: 569: 549: 524: 354: 352:{\displaystyle i_{1}} 327: 325:{\displaystyle i_{0}} 297: 275: 246: 224: 200: 162: 160:{\displaystyle w_{i}} 132: 112: 767: 763:To find the ranking 749:incremental learning 618: 598: 578: 558: 538: 366: 336: 309: 286: 273:{\displaystyle P(x)} 255: 235: 213: 171: 144: 121: 110:{\displaystyle P(x)} 92: 73:it is also used for 917:10.1007/11569541_22 861:. pp. 397–402. 653:Comparison with SOM 485: 421: 396: 231:Sample data vector 209:For each time step 67:pattern recognition 55:vector quantization 35:self-organizing map 1142:. pp. 33–41. 1117:10.1007/BF01413708 818: 735:Plastic neural gas 674:Growing neural gas 647:k-means clustering 624: 604: 584: 564: 544: 534:In the algorithm, 519: 464: 400: 369: 349: 322: 292: 270: 241: 219: 195: 157: 127: 107: 71:k-means clustering 59:speech recognition 33:, inspired by the 1159:978-1-4503-6918-3 1078:978-0-7803-9048-5 961:978-3-540-76724-4 926:978-3-540-29411-5 889:978-3-540-67354-5 627:{\displaystyle t} 295:{\displaystyle x} 244:{\displaystyle x} 222:{\displaystyle t} 130:{\displaystyle x} 1329: 1279: 1246: 1245: 1211: 1205: 1204: 1170: 1164: 1163: 1151: 1135: 1129: 1128: 1100: 1091: 1090: 1056: 1047: 1046: 1028: 1019:(8): 1041–1058. 1008: 999: 998: 996: 995: 975: 966: 965: 953: 937: 931: 930: 900: 894: 893: 869: 863: 862: 852: 843: 827: 825: 824: 819: 817: 816: 792: 791: 779: 778: 639:gradient descent 633: 631: 630: 625: 613: 611: 610: 605: 593: 591: 590: 585: 573: 571: 570: 565: 553: 551: 550: 545: 528: 526: 525: 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Index

Nerve gas
artificial neural network
self-organizing map
Thomas Martinetz
Klaus Schulten
feature vectors
data compression
vector quantization
speech recognition
image processing
pattern recognition
k-means clustering
cluster analysis
probability distribution
feature vectors
gradient descent
cost function
k-means clustering
Hebb
incremental learning
streaming data
"A "neural gas" network learns topologies"
Elsevier
"Competitive learning methods for efficient Vector Quantizations in a speech recognition environment"
MICAI 2000: Advances in artificial intelligence : Mexican International Conference on Artificial Intelligence, Acapulco, Mexico, April 2000 : proceedings
ISBN
978-3-540-67354-5
Yanxi Liu
doi
10.1007/11569541_22

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