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Station elements as of December 2022[update] (exploded view) The International Space Station(ISS) is a large space stationassembledand maintained in low Earth orbitby a collaboration of five space agencies and their contractors: NASA(United States), Roscosmos(Russia), JAXA(Japan), ESA(Europe), and CSA(Canada).
Starlink is a satellite internet constellation operated by Starlink Services, LLC, a wholly-owned subsidiary of American aerospace company SpaceX,[3] providing coverage to over 70 countries. It also aims to provide global mobile broadband.[4] SpaceX started launching Starlink satellites in 2019. As of early March 2024, it consists of over ...
- Definitions
- Applications
- Term Frequency-Inverse Document Frequency Weights
- Advantages
- Limitations
- Models Based on and Extending The Vector Space Model
- Software That Implements The Vector Space Model
- Further Reading
In this section we consider a particular vector space model based on the bag-of-wordsrepresentation. Documents and queries are represented as vectors. 1. d j = ( w 1 , j , w 2 , j , … , w n , j ) {\displaystyle d_{j}=(w_{1,j},w_{2,j},\dotsc ,w_{n,j})} 2. q = ( w 1 , q , w 2 , q , … , w n , q ) {\displaystyle q=(w_{1,q},w_{2,q},\dotsc ,w_{n,q})} Eac...
Candidate documents from the corpus can be retrieved and ranked using a variety of methods. Relevance rankings of documents in a keyword search can be calculated, using the assumptions of document similaritiestheory, by comparing the deviation of angles between each document vector and the original query vector where the query is represented as a v...
In the classic vector space model proposed by Salton, Wong and Yang the term-specific weights in the document vectors are products of local and global parameters. The model is known as term frequency-inverse document frequency model. The weight vector for document d is v d = [ w 1 , d , w 2 , d , … , w N , d ] T {\displaystyle \mathbf {v} _{d}=[w_{...
The vector space model has the following advantages over the Standard Boolean model: 1. Allows ranking documents according to their possible relevance 2. Allows retrieving items with a partial term overlap Most of these advantages are a consequence of the difference in the density of the document collection representation between Boolean and term f...
The vector space model has the following limitations: 1. Query terms are assumed to be independent, so phrases might not be represented well in the ranking 2. Semantic sensitivity; documents with similar context but different term vocabulary won't be associated Many of these difficulties can, however, be overcome by the integration of various tools...
Models based on and extending the vector space model include: 1. Generalized vector space model 2. Latent semantic analysis 3. Term 4. Rocchio Classification 5. Random indexing 6. Search Engine Optimization
The following software packages may be of interest to those wishing to experiment with vector models and implement search services based upon them.
G. Salton (1962), "Some experiments in the generation of word and document associations" Proceeding AFIPS '62 (Fall) Proceedings of the December 4–6, 1962, fall joint computer conference, pages 234...G. Salton, A. Wong, and C. S. Yang (1975), "A Vector Space Model for Automatic Indexing" Communications of the ACM, vol. 18, nr. 11, pages 613–620. (Article in which a vector space model was presen...David Dubin (2004), The Most Influential Paper Gerard Salton Never Wrote (Explains the history of the Vector Space Model and the non-existence of a frequently cited publication)Four-dimensional space ( 4D) is the mathematical extension of the concept of three-dimensional space (3D). Three-dimensional space is the simplest possible abstraction of the observation that one needs only three numbers, called dimensions, to describe the sizes or locations of objects in the everyday world.
In mathematics, a spherical coordinate system is a coordinate system for three-dimensional space where the position of a given point in space is specified by three numbers, ( r, θ, φ ): the radial distance of the radial line r connecting the point to the fixed point of origin (which is located on a fixed polar axis, or zenith direction axis ...
Mount Fuji (富士山, Fujisan, Japanese: [ɸɯ (d)ʑisaɴ] ) is an active stratovolcano located on the Japanese island of Honshu, with a summit elevation of 3,776.24 m (12,389 ft 3 in).It is the tallest mountain in Japan, the second-highest volcano located on an island in Asia (after Mount Kerinci on the Indonesian island of Sumatra), and seventh-highest peak of an island on Earth.
The earliest datable record of an aurora was recorded in the Bamboo Annals, a historical chronicle of the history of ancient China, in 977 or 957 BC. An aurora was described by the Greek explorer Pytheas in the 4th century BC. Seneca wrote about auroras in the first book of his Naturales Quaestiones, classifying them, for instance, as pithaei ('barrel-like'); chasmata ('chasm'); pogoniae ...
