L Linear Hashing
نویسندگان
چکیده
Linear Hashing is a dynamically updateable diskbased index structure which implements a hashing scheme and which grows or shrinks one bucket at a time. The index is used to support exact match queries, i.e., find the record with a given key. Compared with the BC-tree index which also supports exact match queries (in logarithmic number of I/Os), Linear Hashing has better expected query cost O(1) I/O. Compared with Extendible Hashing, Linear Hashing does not use a bucket directory, and when an overflow occurs, it is not always the overflown bucket that is split. The name Linear Hashing is used because the number of buckets grows or shrinks in a linear fashion. Overflows are handled by creating a chain of pages under the overflown bucket. The hashing function changes dynamically and at any given instant there can be at most two hashing functions used by the scheme. Historical Background
منابع مشابه
Image authentication using LBP-based perceptual image hashing
Feature extraction is a main step in all perceptual image hashing schemes in which robust features will led to better results in perceptual robustness. Simplicity, discriminative power, computational efficiency and robustness to illumination changes are counted as distinguished properties of Local Binary Pattern features. In this paper, we investigate the use of local binary patterns for percep...
متن کاملCompressed Image Hashing using Minimum Magnitude CSLBP
Image hashing allows compression, enhancement or other signal processing operations on digital images which are usually acceptable manipulations. Whereas, cryptographic hash functions are very sensitive to even single bit changes in image. Image hashing is a sum of important quality features in quantized form. In this paper, we proposed a novel image hashing algorithm for authentication which i...
متن کاملA trade-off between collision probability and key size in universal hashing using polynomials
Let IF be a finite field and suppose that a single element of IF is used as an authenticator (or tag). Further, suppose that any message consists of at most L elements of IF. For this setting, usual polynomial based universal hashing achieves a collision bound of (L− 1)/|IF| using a single element of IF as the key. The well-known multi-linear hashing achieves a collision bound of 1/|IF| using L...
متن کاملb-Bit Minwise Hashing for Large-Scale Linear SVM
Linear Support Vector Machines (e.g., SVM, Pegasos, LIBLINEAR) are powerful and extremely efficient classification tools when the datasets are very large and/or highdimensional, which is common in (e.g.,) text classification. Minwise hashing is a popular technique in the context of search for computing resemblance similarity between ultra high-dimensional (e.g., 2) data vectors such as document...
متن کاملPerformance of Linear Hashing Schemes for Primary Key Retrieval
Linear hashing is one of the most attractive dynamic hashing schemes. Linear hashing with partial expansions and linear hashing with priority splitting are two variations with improved space and time performance. Here, we propose a new structure, which is termed linear hashing with partial expansions and priority splitting. The above four structures are compared by simulation and it is shown th...
متن کامل