Cellular Automata Evolution for Pattern Recognition Pradipta Maji Center for Soft Computing Research Indian Statistical Institute, Kolkata, 700 108, INDIA Under the supervision of Prof. P Pal Chaudhuri Prof. Debesh K Das Professor Emeritus Professor Dept. of Comp. Sci. & Tech. Dept. of Comp. Sci. & Engg. Bengal Engineering College (DU), Shibpur, INDIA Jadavpur University, INDIA
Introduction Cellular Automata (CA) promising research area Artificial Intelligence (AI) Artificial Life (ALife) Considerable research in modeling tool image processing language recognition pattern recognition VLSI testing Cellular Automata (CA) learns association from a set of examples apply this knowledge-base to handle unseen cases such associations effective for classifying patterns
Contribution of the Thesis Analysis and synthesis of linear boolean CA (MACA) CA with only XOR logic application of MACA in pattern recognition data mining image compression fault diagnosis of electronic circuit Analysis and synthesis of non-linear boolean CA (GMACA) CA with all possible logic application of non-linear CA in pattern recognition Analysis and synthesis of fuzzy CA (FMACA) CA with fuzzy logic application of fuzzy CA in pattern recognition
Cellular Automata (CA) A special type of computing model 50 s - J Von Neumann 80 s - S. Wolfram A CA displays three basic characteristics Simplicity: Basic unit of CA cell is simple Vast parallelism: CA achieves parallelism on a scale larger than massively parallel computers Locality: CA characterized by local connectivity of its cell all interactions take place on a purely local basis a cell can only communicate with its neighboring cells interconnection links usually carry only a small amount of information no cell has a global view of the entire system
Cellular Automata (CA) A computational model with discrete cells updated synchronously Uniform CA, hybrid / non-uniform CA, null boundary CA, periodic boundary CA Each cell can have 256 different rules.. 2 - state 3-neighborhood CA cell Clock Input output 0/1 From left neighbor Combinati onal Logic From right neighbor
For 2nd Cell Rule 230 PS NS 111 1 110 1 101 1 100 0 011 0 010 1 001 1 000 0 CA State Transition 0 0 1 1 98 230 226 107 0 1 1 1 98 230 226 107 0 0 1 0 3 7 2
Different Types of CA Linear CA Based on XOR logic Total 7 rules (60, 90, 102, 150, 170, 204, 240) Can be expressed through matrix (T), characteristic polynomial Next state of the CA cell P(t+1) = T. P(t) 60 102 150 204 Additive CA Based on XOR and XNOR logic Total 14 rules (linear rules + 195,165,153,105,85,51,15) Can be expressed through matrix, inversion vector, characteristic polynomial The next state of the CA cell P(t+1) = T. P(t) + F T = 1 0 0 0 0 1 1 0 0 1 1 1 0 0 0 1 60 153 105 204 F = 0 1 1 0
Additive Cellular Automata XOR Logic XNOR Logic Rule 60 : q I (t+1) = q I-1 (t) q I (t) Rule 90 : q I (t+1) = q I-1 (t) q I+1 (t) Rule 195 : q I (t+1) = q I-1 (t) q I (t) Rule 165 : q I (t+1) = q I-1 (t) q I+1 (t) Rule 102 : q I (t+1) = q I (t) q I+1 (t) Rule 153 : q I (t+1) = q I (t) q I+1 (t) Rule 150 : q I (t+1) = q I-1 (t) q I (t) q I-1 (t) Rule 105 : q I (t+1) = q I-1 (t) q I (t) q I-1 (t) Rule 170 : q I (t+1) = q I-1 (t) Rule 204 : q I (t+1) = q I (t) Rule 85 : q I (t+1) = q I-1 (t) Rule 51 : q I (t+1) = q I (t) Rule 240 : q I (t+1) = q I+1 (t) Rule 15 : q I (t+1) = q I+1 (t)
CA - State Transition Diagram 0 6 9 15 Group CA 13 7 12 3 14 11 5 2 8 1 4 10 2 5 7 8 13 10 3 4 6 9 12 11 15 14 Non-group Cellular Automata Linear Non-linear Fuzzy 0 1 Non-group CA Associative Memory MACA GMACA FMACA Perform pattern recognition task
Pattern Recognition Pattern Recognition/Classification most important foundation stone of knowledge extraction methodology demands automatic identification of patterns of interest (objects, images) from its background (shapes, forms, outlines, etc) conventional approach machine compares given input pattern with each of stored patterns identifies the closest match time to recognize the closest match O(k) recognition slow Associative Memory Entire state space - divided Transient into some pivotal points Transient Transient 1. MACA (linear) 2. GMACA (non-linear) 3. FMACA (fuzzy) States close to pivot - associated with that pivot Time to recognize a pattern - Independent of number of stored patterns
Multiple Attractor CA (MACA) Employs linear CA rules State with self loop attractor Transient states and attractor form attractor basin Behaves as an associative memory Forms natural clusters 10001 01001 10010 10011 10000 11000 01000 01010 11011 01011 00001 00000 11001 00010 00011 11010 10100 10101 10110 10111 01100 11100 01101 01110 11111 01111 00101 00100 11101 00110 00111 11110
Multiple Attractor CA (MACA) Next state: P(t+1) = T. P(t) Characteristic Polynomial: X (n-m) (1+X) m where m=log 2 (k) n denotes number of CA cell k denotes number of attractor basins Depth d of MACA number of edges between a non-reachable state and an attractor state Attractor of a basin: P(t+d) = T d P(t) m-bit positions pseudo-exhaustive: extract PEF (pseudo-exhaustive field) from attractor state Problem: Complexity of identification of attractor basin is O(n 3 ) Exponential search space Redundant solutions
Chromosome of Genetic Algorithm T = 1 1 0 0 0 1 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 1 0 Rule vector 102 60 204 204 240 Matrix 1 1 1 1 0.. 1 0 Characteristic polynomial x 3 (1+x) 2 Elementary divisors x 3 (1+x) 2 x 2 (1+x) (1+x) x x 2 (1+x) ( 1+x) x
Dependency Vector/Dependency String T = 1 1 0 0 0 1 1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 1 0 T1 = 1 1 0 1 1 0 0 0 1 Characteristic polynomial x 2 (1+x) Characteristic polynomial x 3 (1+x) 2 T2 = 1 0 1 0 Characteristic polynomial x(1+x) Matrix T is obtained from T1 and T2 by Block Diagonal Method
Dependency Vector/Dependency String T d = 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 1 0 Dependency Vector DV1 = < 0 0 1 > Dependency String DS = < 0 0 1 > < 1 0 > Dependency String DS = < 0 0 1 2 0 > T1 d = T2 d = 0 0 0 0 0 0 0 0 1 1 0 1 0 0 0 1 2 0 Dependency Vector DV1 = < 1 0 >
Dependency Vector/Dependency String Zero basin of T1 + Zero basin of T2 ----- Zero basin of T1 + Non-zero basin of T2 --- Non-zero basin of T1 + Zero basin of T2 ---- Non-zero basin of T1 + Non-zero basin of T2 --- PEF Bits 0 0 0 1 1 0 1 1 DV1 contributes 1 st PEF Bits DV2 contributes 2 nd PEF Bits PEF = [PEF1] [PEF2] = [DS.P] = [DV1.P1] [DV2.P2] P = [ 1 1 1 1 1 ] DS = [ 0 0 1 2 0 ] PEF = [PEF1][PEF2] = [<0 0 1><1 1 1>][<1 0><1 1>] = 1 1
Matrix/Rule from Dependency String 0 in DV T1 = [ 0 ] 1 in DV T2 = [ 1 ] 11 in DV T3 = [T1] 1 0 0 101 in DV T4 = DS = < 1 0 1 1 2 2 2> [T1] 1 0 0 1 1 0 1 1 DV = < 1 0 1 1 > DV = < 1 1 1 > 1 1 0 0 0 0 0 0 1 1 0 0 0 0 T1 = 1 1 0 0 0 1 1 0 0 1 1 1 T2 = 1 1 0 0 0 1 0 0 0 T = 0 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 CA Rule Vector <102, 102, 150, 0, 102, 170, 0> 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0
Dependency Vector/Dependency String Characteristic polynomial x 4 (1+x) T1 = 0 1 0 0 0 0 0 0 0 0 0 1 1 1 0 0 0 0 0 0 0 0 0 1 0 T2 = 0 1 0 0 0 0 0 1 0 0 0 1 1 1 0 0 0 1 0 0 0 0 0 1 0 T3 = 0 1 0 0 0 0 0 1 0 0 0 1 1 1 0 0 0 1 0 0 0 0 0 0 0 <170, 0, 150, 0, 240> <170, 0, 150, 0, 240> <170, 0, 150, 0, 240> Dependency Vector <0 1 1 1 0> Identification of attractor basins in O(n) Reduction of search space
Image Compression Block diagram of codebook generation scheme Training Images Spatial Domain High Compression ratio Acceptable image quality 16 X 16 Set 8 X 8 Set 4 X 4 Set Applications - Human Portraits TSVQ 16 X 16 Codebook 8 X 8 Codebook 4 X 4 Codebook
Tree-Structured Vector Quantization N X N Set S1, S2, S3, S4 Cluster 1 Cluster 2 S1, S2 S3, S4 Centroid 1 Centroid 2 S1 S2 S3 S4 Clusters and centroids generation using Tree-Structured Vector Quantization (TSVQ) Logical structure of multi-class classifier equivalent to PTSVQ
MACA Based Two Stage Classifier Input Layer Classifier 1 Hidden Layer Classifier 2 Output Layer Classifier 1: n-bit DS consists of m DVs Classifier 2: m-bit DV No of Bits (n) Value of PEF (m) Memory Size Ratio Software Hardware 100 5 0.795 0.942 15 0.003 0.010 MSR (software) = (n+m) / (n+2 m ) 200 5 15 0.884 0.006 0.969 0.019 MSR (hardware) = (3n+3m-4) / (3n-2+2 m ) 300 5 15 0.919 0.009 0.979 0.028
Image Compression Original Decompressed Execution Time (in milli seconds) Block Size Full Search TSVQ CA 4 X 4 0.0121 0.00824 0.00562 compression 96.43%, PSNR 32.81 8 X 8 0.0473 0.03312 0.01367 16 X 16 0.1941 0.13192 0.04102 compression 95.66%, PSNR 34.27 High compression Acceptable image quality Higher speed
MACA based Tree-Structured Classifier Selection of MACA: Diversity of i th attractor basin (node): M i = max{n ij } / j N ij where N ij - number of tuples of class j covered by i th attractor basin M i 1, i th attractor indicates class j for which N ij is maximum Figure of Merit: FM = 1/k i M i where k denotes number of attractor basins MACA 1 MACA 2 II IV MACA 3 MACA 4 I III IV I II III I II IV
Fault Diagnosis of Digital Circuit Fault Injection Diagnosis of an example CUT EC Set of Test Vect ors Module 1 Module 2 CUT EC S A Signature Set Pattern Classifier MACA Fault Injection CUT (n,p) C1908(25,1801) # Partition 6 MACA 98.83 Dictionary 96.03 Memory 0.9106 C6288(32,7648) 6 99.72 99.33 0.2104 C7552(108,7053) 6 98.96 98.81 0.2238 S4863(16,4123) 10 92.43 89.63 0.7504 S3271(14,2585) 8 97.05 79.54 0.9308 S6669(55,6358) 10 99.94 95.12 0.4426
Fault Diagnosis of Analog Circuit OTA1 OTA2 Component OTA1 # Samples 8970 Detected 8962 Not detected 8 SR 99.91 V in C1 V out C2 OTA2 C1 5430 5430 5424 5421 6 9 99.88 99.83 C2 5610 5603 7 99.87 Component # Samples Detected Not detected SR OTA3 OTA1 OTA2 OTA3 7201 4321 4441 7193 4306 4436 8 15 5 99.89 99.65 99.88 V in OTA1 X1 OTA2 X2 C1 C2 4297 4321 4181 4219 116 102 97.30 97.64 X1: Output of BPF X2: Output of LPF
Performance on STATLOG Dataset Classification Accuracy (%) Memory Overhead (Kbyte) Dataset Bayesian C4.5 MLP MACA Bayesian C4.5 MLP MACA Australian 83.4 85.8 84.7 86.5 19 37.85 1.93 8.04 Diabetes 72.9 74.2 75.3 75.9 14 27.15 0.44 9.96 DNA 90.3 93.3 91.4 87.9 1000 1067.96 37.22 50.86 German 66.8 67.4 67.1 74.6 49 99.31 13.64 17.42 Heart 80.1 79.3 80.7 86.6 9.8 19.46 1.52 3.17 Satimage 85.4 85.2 86.2 77.5 669 709.72 11.33 222.74 Shuttle 99.9 99.9 99.9 94.1 1500 1513.57 0.71 55.17 Letter 87.4 86.6 67.2 84.4 766 1299.28 2.57 354.11 Vehicle 72.9 68.5 79.3 78.7 47.02 72.14 1.32 29.83 Segment 96.7 94.6 94.4 89.5 121.89 370.42 2.74 24.51
MACATree VS C4.5 on Statlog Dataset STATLOG Dataset Classifn. Accuracy C4.5 MACA Memory Overhead C4.5 MACA No of Nodes C4.5 MACA Retrieval Time(ms) C4.5 MACA Australian 85.8 86.5 37.85 8.04 35 27.3 461 4 Diabetes 74.2 75.9 27.15 9.96 39 34.2 1739 10 DNA 93.3 87.9 1067.96 50.86 127 124.3 655 494 German 67.4 74.6 99.31 17.42 134 49.8 1967 19 Heart 79.3 86.6 19.46 3.17 33 8.6 1819 17 Satimage 85.2 77.5 709.72 222.74 433 199.2 2255 4943 Shuttle 99.9 94.1 1513.57 55.17 49 47.2 3985 6633 Letter 86.6 84.4 1299.28 354.11 2107 524.6 14352 5633 Vehicle 68.5 78.7 72.14 29.83 139 50.8 1963 28 Segment 94.6 89.5 370.42 24.51 82 39.7 2508 58 Comparable classification accuracy Low memory overhead Lesser number of intermediate nodes Lesser retrieval time
Conclusion Advantages: Explore computational capability of MACA Introduction of Dependency Vector (DV)/String (DS) to characterize MACA Reduction of complexity to identify attractor basins from O(n 3 ) to O(n) Elegant evolutionary algorithm combination of DV/DS and GA MACA based tree-structured pattern classifier Application of MACA in Classification image compression fault diagnosis of electronic circuits Codon to amino acid mapping, S-box of AES Problems: Linear MACA employs only XOR logic, functionally incomplete Distribution of each attractor basin is even Can handle only binary patterns Solutions: Nonlinear MACA (GMACA) Fuzzy MACA (FMACA)
Generalized MACA (GMACA) Employs non-linear hybrid rules with all possible logic Cycle or attractor length greater than 1 Can perform pattern recognition task Behaves as an associative memory 0100 1000 1101 0111 1010 0001 0011 1100 1001 0101 0010 Rule vector: <202,168,218,42> 1011 0110 1110 0000 P1 attractor-1 P2 attractor-2 1111
Basins of Attraction (Theoretical) n = 50 Error correcting capability at single bit noise k = 10 Error correcting capability at multiple bit noise
Distribution of CA Rule (Theoretical) Degree of Homogeneity DH = 1- r/4 where r = number of 1 s of a rule More homogeneous less probability of occurrence
Synthesis of GMACA Phase I: Random Generation of a directed sub-graph Phase II: State transition table from sub-graph Phase III: GMACA rule vector from State transition table For 2nd Cell:- 111 1 110 1 101 1 100 0 011 1 010 0 001 0 000 0 Rule 232 Basin 2 0100 1000 0001 Basin 1 0010 0000 g1 Present State 1110 1011 1101 0111 1111 Basin Next State 0111 0111 0111 1111 1111 Present State 1110 1011 1101 Basin 2 0111 1111 Next State 1 0100 0001 1000 0001 0001 0000 0000 0000 0010 0000 g2
Resolution of Collision: Genetic Algorithm if n 0 = n 1 ; next state is either `0 or `1 if n 0 > n 1 ; next state is `0 if n 0 < n 1 ; next state is `1 where n 0 = Occurrence of state `0 for a configuration n 1 = Occurrence of state `1 g1 g2.. gk Example chromosome format each g x a basin of a pattern P x k numbers of genes in a chromosome Each gene - a single cycle directed sub-graph with p number of nodes, where p = 1 + n
Maximum Permissible Noise/Height Minimum value of maximum permissible height h max = 2 Minimum value of maximum permissible noise r max = 1
Performance Analysis of GMACA Higher memorizing capacity than Hopfield network Cost of computation is constant depends on transient length of CA
Basins of Attraction (Experimental) n = 50 k = 10
Distribution of CA Rule (Experimental)
Conclusion Advantages: Explore computational capability of non-linear MACA Characterization of basins of attraction of GMACA Fundamental results to characterize GMACA rules Reverse engineering method to synthesize GMACA Combination of reverse engineering method and GA Higher memorizing capacity than Hopfield network Problems: Can handle only binary patterns Solutions: Fuzzy MACA (FMACA)
Fuzzy Cellular Automata (FCA) A linear array of cells Each cell assumes a state - a rational value in [0, 1] Combines both fuzzy logic and Cellular Automata Out of 256 rules, 16 rules are OR and NOR rules (including 0 and 255) Boolean Function Opeartion FCA Operation OR (a + b) min{1, (a + b)} AND (a.b) (a.b) NOT (~a) (1 a)
Fuzzy Cellular Automata (FCA) OR Logic NOR Logic Rule 170 : q I (t+1) = q I-1 (t) Rule 204 : q I (t+1) = q I (t) Rule 85 : q I (t+1) = q I-1 (t) Rule 51 : q I (t+1) = q I (t) Rule 238 : q I (t+1) = q I (t) + q I+1 (t) Rule 17 : q I (t+1) = q I (t) + q I+1 (t) Rule 240 : q I (t+1) = q I+1 (t) Rule 15 : q I (t+1) = q I+1 (t) Rule 250 : q I (t+1) = q I-1 (t) + q I+1 (t) Rule 252 : q I (t+1) = q I-1 (t) + q I (t) Rule 5 : q I (t+1) = q I-1 (t) + q I+1 (t) Rule 3 : q I (t+1) = q I-1 (t) + q I (t) Rule 254 : q I (t+1) = q I-1 (t) + q I (t) + q I+1 (t) Rule 1 : q I (t+1) = q I-1 (t) + q I (t) + q I+1 (t)
Fuzzy Cellular Automata (FCA) 16 OR and NOR rules can be represented by n x n matrix T and an n dimensional binary vector F S i (t) represents the state of i th cell at t th time instant S i (t+1) = F i -min{1, Σ j T ij.s j (t)} where T 1 if next state of ij = ith cell dependents on j th cell 0 otherwise F = Inversion vector, contains 1 where NOR rule is applied 1 1 0 0 0 4-cell null boundary hybrid FCA <238,1,238,3> T = 1 1 1 0 0 0 1 1 F = 1 0 0 0 1 1 1
Fuzzy Multiple Attractor CA (FMACA)
Fuzzy Multiple Attractor CA (FMACA) Dependency Vector (DV) corresponding to matrix Derived Complement Vector (DCV) corresponding to inversion vector Pivot cell (PC) represents an attractor basin uniquely State of Pivot Cell (PC) of attractor of the basin where a state belongs q m = min {1, Σ j DCV j -DV j.s j (t) } Size of attractor basins equal as well as unequal Matrix, inversion vector from DV/DCV
Fuzzy Multiple Attractor CA (FMACA) 0.0 1.0 1.0 1.0 0.0 0.5 0.5 1.0 1.0 0.5 0.0 0.5 0.0 0.5 0.5 0.5 1.0 0.5 1.0 0.0 1.0 1.0 0.5 1.0 0.5 0.5 1.0 0.5 0.5 0.0 1.0 1.0 0.5 0.5 0.5 0.5 0.0 1.0 0.5 1.0 1.0 1.0 1.0 1.0 0.0 1.0 0.0 0.0 1.0 0.5 0.0 1.0 0.5 0.5 0.0 0.5 1.0 0.5 1.0 0.0 0.0 1.0 0.0 0.5 0.0 1.0 0.0 0.0 1.0 0.0 0.0 0.5 1 1 0 T = 0 0 1 0 1 F = 0 DV = 1 DCV = 0 0 0.0 0.0 0.0 0.0 0.5 0.0 0 0 0 0 1 0 0.5 0.0 0.0
Fuzzy Multiple Attractor CA (FMACA) 0.0 1.0 0.0 1.0 0.0 0.5 0.5 1.0 0.0 0.5 0.0 0.5 0.0 0.5 0.5 0.5 1.0 0.5 1.0 0.0 0.0 1.0 0.5 0.0 0.5 0.5 0.0 0.5 0.5 1.0 1.0 1.0 0.5 0.5 0.5 0.5 0.0 1.0 0.5 1.0 1.0 0.0 1.0 1.0 1.0 1.0 0.0 1.0 1.0 0.5 1.0 1.0 0.5 0.5 0.0 0.5 0.0 0.5 1.0 1.0 0.0 1.0 1.0 0.5 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.5 1 1 0 T = 0 0 1 0 1 F = 1 DV = 1 DCV = 0 0 0.0 0.0 1.0 0.0 0.5 1.0 0 0 0 1 1 1 0.5 0.0 1.0
FMACA based Tree-Structured Classifier FMACA based tree-structured pattern classifier Can handle binary as well as real valued datasets Provides equal and unequal size of attractor basins Combination of GA and DV/DCV FMACA 1 FMACA 2 II IV FMACA 3 FMACA 4 I III IV I II III I II IV
Experimental Setup Randomly generate K number of centroids Around each centroid, generate t number of tuples 50 % patterns are taken for training 50 % patterns are taken for testing A 1 D min A 2 d max A K
Performance Analysis of FMACA Generalization of FMACA tree Dataset Depth Training Accuracy Testing Accuracy Breadth Depth: Number of layers from root to leaf Breadth: Number of intermediate nodes Can generalize dataset irrespective of classes, tuples, attributes (n=5,k=2,t=4000) 1 2 3 4 16.9 81.8 97.7 98.4 15.6 80.9 91.6 92.4 1 21 35 9 Attributes (n) Size (t) No of Classes FMACA C4.5 6 6000 4 8 96.68 89.26 93.10 81.60 Higher classification accuracy compared to C4.5 8 10000 6 10 85.91 85.61 79.60 73.93 10 10000 4 8 83.82 74.01 77.10 66.90
Performance Analysis of FMACA Generation Time (ms) Retrieval Time (ms) Dataset FMACA C4.5 FMACA C4.5 (n=5,k=2,t=2000) 14215 273 3 306 High generation time - but, one time cost Lower retrieval time compared to C4.5 (n=5,k=2,t=20000) 52557 756 80 812 (n=6,k=2,t=2000) 722725 162 4 259 (n=6,k=2,t=20000) 252458 791 35 874 Attributes (n) Size (t) No of Classes FMACA C4.5 6 6000 4 8 1362 1331 5109 6932 Lower memory overhead compared to C4.5 8 8000 6 8 1261 1532 9519 8943 10 10000 6 10 1364 1481 7727 7984
Performance on STATLOG Dataset Classification Accuracy (%) Dataset FMACA MACA DNA 88. 1 87.9 Satimage 81.9 77.5 Shuttle 93.1 94.1 Letter 85.1 84.4 Number of CA cells FMACA MACA 180 180 36 540 9 567 16 1008 No of Nodes of Tree FMACA MACA 122.1 124.3 161.6 199.2 51.8 47.2 661.8 524.6 Memory Overhead Retrieval Time (ms) Comparable accuracy Lesser CA cells Lesser memory overhead Lesser retrieval time Dataset DNA Satimage Shuttle Letter FMACA 51.22 189.62 18.29 261.08 MACA 50.86 222.74 55.17 354.11 FMACA 491 2419 1982 1382 MACA 494 4943 6633 5633
Conclusion Introduction of fuzzy CA in pattern recognition New mathematical tools Dependency matrix, Dependency vector Complement vector, Derived complement vector Reduction of complexity to identify attractors from O(n 3 ) to O(n) Both equal and unequal size of attractor basins Movement of patterns from one to another basin Reduction of search space Elegant evolutionary algorithm combination of DV/DCV and GA FMACA based tree-structured pattern classifier
Future Extensions Applications in pattern clustering, mix-mode learning Theoretical analysis of memorizing capacity of non-linear CA Combination of fuzzy set and fuzzy CA 1-D CA to 2-D CA Development of hybrid systems using CA CA + neural network + fuzzy set CA + fuzzy set + rough set Boolean CA to multi-valued / hierarchical CA Application of CA in Bioinformatics Medical Image Analysis Image Compression Data Mining
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