enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Query optimization - Wikipedia

    en.wikipedia.org/wiki/Query_optimization

    The set of query plans examined is formed by examining the possible access paths (e.g., primary index access, secondary index access, full file scan) and various relational table join techniques (e.g., merge join, hash join, product join). The search space can become quite large depending on the complexity of the SQL query. There are two types ...

  3. Database index - Wikipedia

    en.wikipedia.org/wiki/Database_index

    To process this statement without an index the database software must look at the last_name column on every row in the table (this is known as a full table scan). With an index the database simply follows the index data structure (typically a B-tree ) until the Smith entry has been found; this is much less computationally expensive than a full ...

  4. Image compression - Wikipedia

    en.wikipedia.org/wiki/Image_compression

    Image compression is a type of data compression applied to digital images, to reduce their cost for storage or transmission. Algorithms may take advantage of visual perception and the statistical properties of image data to provide superior results compared with generic data compression methods which are used for other digital data. [1]

  5. Group 4 compression - Wikipedia

    en.wikipedia.org/wiki/Group_4_compression

    Group 4 compression is available in many proprietary image file formats as well as standardized formats such as TIFF, CALS, CIT (Intergraph Raster Type 24) and the PDF document format. G4 offers a small improvement over G3-2D by removing the end-of-line (EOL) codes. G3 and G4 compression both treat an image as a series of horizontal black ...

  6. Data compression - Wikipedia

    en.wikipedia.org/wiki/Data_compression

    Data compression aims to reduce the size of data files, enhancing storage efficiency and speeding up data transmission. K-means clustering, an unsupervised machine learning algorithm, is employed to partition a dataset into a specified number of clusters, k, each represented by the centroid of its points.

  7. Determining the number of clusters in a data set - Wikipedia

    en.wikipedia.org/wiki/Determining_the_number_of...

    The average silhouette of the data is another useful criterion for assessing the natural number of clusters. The silhouette of a data instance is a measure of how closely it is matched to data within its cluster and how loosely it is matched to data of the neighboring cluster, i.e., the cluster whose average distance from the datum is lowest. [8]

  8. Comparison of graphics file formats - Wikipedia

    en.wikipedia.org/wiki/Comparison_of_graphics...

    AV1 Image File Format Alliance for Open Media (AOMedia) AV1.avif image/avif General purpose royalty-free BAY: Casio RAW Casio.bay BMP: raw-data unencoded or encoded bitmap simple colour image format, far older than Microsoft; some .bmp encoding formats developed/owned by Microsoft.bmp, .dib, .rle,.2bp (2bpp) image/x-bmp Used by many 2D ...

  9. Lossy compression - Wikipedia

    en.wikipedia.org/wiki/Lossy_compression

    While data reduction (compression, be it lossy or lossless) is a main goal of transform coding, it also allows other goals: one may represent data more accurately for the original amount of space [5] – for example, in principle, if one starts with an analog or high-resolution digital master, an MP3 file of a given size should provide a better ...