Found 426 Questions for Data Mining

What is Randomized Algorithms and Data Stream Management System in data mining?

Updated on 17-Feb-2022 11:28:41
Randomized Algorithms − Randomized algorithms in the form of random sampling and blueprint, are used to deal with large, high-dimensional data streams. The need of randomization leads to simpler and more effective algorithms in contrast to known deterministic algorithms.If a randomized algorithm continually returns the correct answer but the running times change, it is called a Las Vegas algorithm. In contrast, a Monte Carlo algorithm has bounds on the running time but cannot restore the true result. It can usually consider Monte Carlo algorithms. The importance of a randomized algorithm is simply as a probability distribution over a group of ... Read More

What is Sequential Exception Technique?

Updated on 17-Feb-2022 11:18:57
The sequential exception technique simulates the method in which humans can distinguish unusual sets from between a sequence of supposedly like objects. It helps implicit redundancy of the data.Given a data set, D, of n objects, it construct a sequence of subsets, {D1, D2, ..., Dm}, of these objects with 2 ≤ m ≤ n including$$\mathrm{D_{j−1}\subset D_{j}\:\:where\: D_{j}\subseteq D}$$Dissimilarities are assessed between subsets in the series. The technique learns the following terms which are as follows −Exception set − This is the set of deviations or outliers. It is defined as the smallest subset of objects whose removal results in ... Read More

How can we approach the problem of clustering with obstacles?

Updated on 17-Feb-2022 11:08:03
A partitioning clustering method is desirable because it minimizes the distance among sets and their cluster centers. If it can choose the k-means method, a cluster center cannot be available given the existence of obstacles.For instance, the cluster can turn out to be in the center of a lake. In other words, the k-medoids method chooses an object inside the cluster as a center and thus guarantees that a problem cannot appear.At each time a new medoid is selected, the distance among each object and its newly selected cluster center has to be recalculated. Because there can be obstacles among ... Read More

What is PROCLUS?

Updated on 17-Feb-2022 11:05:08
PROCLUS stands for Projected Clustering. It is a usual dimension-reduction subspace clustering techniques. That is, rather than starting from individual-dimensional spaces, it begins by finding an original approximation of the clusters in the high-dimensional attribute area.Each dimension is created a weight for each cluster, and the refreshed weights are used in the next iteration to recreate the clusters. This leads to the exploration of dense areas in all subspaces of some convenient dimensionality and prevents the generation of a huge number of overlapped clusters in projected dimensions of lower dimensionality.PROCLUS discover the best group of medoids by a hill-climbing phase ... Read More

What is CLIQUE?

Updated on 17-Feb-2022 11:02:06
CLIQUE was the first algorithm projected for dimension-growth subarea clustering in high-dimensional area. In dimension-growth subarea clustering, the clustering process begins at single-dimensional subspaces and increase upward to higher-dimensional ones.Because CLIQUE partitions each dimension such as grid architecture and decides whether a cell is dense based on the multiple points it includes. It can be looked as an integration of density-based and grid-based clustering approaches.The ideas of the CLIQUE clustering algorithm are as follows −Given a large group of multidimensional data points, the data area is generally not uniformly engaged by the data points. CLIQUE’s clustering recognizes the sparse and ... Read More

What is the working of COWEB?

Updated on 17-Feb-2022 10:58:38
COBWEB incrementally include objects into a classification tree. COBWEB descends the tree along an allocate path, refreshing counts along the method, in search of the “best host” or node at which to define the object.This decision depends on temporarily locating the object in each node and calculating the category utility of the resulting division. The placement that results in the highest element utility must be a best host for the object.COBWEB also calculates the category utility of the partition that can result if a new node is made for the object. The object is located in a current class, or ... Read More

How is this statistical information useful for query answering?

Updated on 17-Feb-2022 10:54:39
The statistical parameters can be used in a top-down, grid-based approaches as follows. First, a layer within the hierarchical architecture is decided from which the query-answering procedure is to start.This layer generally includes a small number of cells. For every cell in the current layer, it can compute the confidence interval (or estimated range of probability) reflecting the cell’s relevancy to the given query.The statistical parameters of higher-level cells can simply be calculated from the parameters of the lower-level cells. These parameters contain the following − the attribute-independent parameter, count, and the attribute-dependent parameters, mean, stdev (standard deviation), min (minimum), ... Read More

What is STING?

Updated on 16-Feb-2022 12:44:19
STING stands for Statistical Information Grid. STING is a grid-based multiresolution clustering method in which the spatial area is divided into rectangular cells. There are several methods of such rectangular cells equivalent to multiple methods of resolution, and these cells form a hierarchical structure each cell at a high level is separation to form several cells at the next lower level.Statistical data regarding the attributes in each grid cell (including the mean, maximum, and minimum values) is precomputed and stored. Statistical parameters of higher-level cells can simply be calculated from the parameters of the lower-level cells.These parameters contain the following ... Read More

What is DENCLUE?

Updated on 16-Feb-2022 12:38:40
Clustering is the significant data mining approaches for knowledge discovery. The clustering is an exploratory data analysis methods that categorizes several data objects into same groups, such as clusters.DENCLUE represents Density-based Clustering. It is a clustering approach depends on a group of density distribution functions. The DENCLUE algorithm use a cluster model depends on kernel density estimation. A cluster is represented by a local maximum of the predicted density function.DENCLUE doesn't operate on records with uniform distribution. In high dimensional space, the data always look like uniformly distributed because of the curse of dimensionality. Hence, DENCLUDE doesn't operate well on ... Read More

What is DBSCAN?

Updated on 16-Feb-2022 12:26:55
DBSCAN stands for Density-Based Spatial Clustering of Applications with Noise. It is a density based clustering algorithm. The algorithm increase regions with sufficiently high density into clusters and finds clusters of arbitrary architecture in spatial databases with noise. It represents a cluster as a maximum group of density-connected points.The concept of density-based clustering includes a number of new definitions as follows −The neighborhood within a radius ε of a given object is known as the εneighborhood of the object.If the ε-neighborhood of an object includes at least a minimum number, MinPts, of objects, then the object is known as core ... Read More
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