Remote sensing is the assessment of information about an object or phenomenon without any physical contact with the particular object and thus in contrast to in situ observation. Remote sensing generally refers to the use of aerial sensor technologies to detect and classify objects on Earth by means of propagated signals. Remote sensing is of two types they are active and passive. Active remote sensing means when a signal is first emitted from aircraft or satellites and passive means when information is recorded.
Open access to the scientific literature means the removal of barriers (including price barriers) from accessing scholarly work. There are two parallel roads towards open access: Open Access articles and self-archiving. Open Access articles are immediately, freely available on their Web site, a model mostly funded by charges paid by the author (usually through a research grant). The alternative for a researcher is self-archiving (i.e., to publish in a traditional journal, where only subscribers have immediate access, but to make the article available on their personal and/or institutional Web sites (including so-called repositories or archives)), which is a practice allowed by many scholarly journals.
Open Access raises practical and policy questions for scholars, publishers, funders, and policymakers alike, including what the return on investment is when paying an article processing fee to publish in an Open Access articles, or whether investments into institutional repositories should be made and whether self-archiving should be made mandatory, as contemplated by some funders.
Last date updated on June, 2014