Text Messaging Categories

IEEE 802.11a & 802.11b essays

IEEE 802.11a & 802.11b essays This report will explore the use of the latest wireless technology, the IEEE standard known as 802.11a, in providing fast, robust, and flexible wireless Local Area Networks that are inexpensive to install and maintain in corporate, government, medical, and educational environments. We will see how it differs from the 802.11b standard. I will enumerate its benefits compared to other connectivity solutions. IEEE 802.11 specification is a WLAN standard that specifies the over the air interface between a wireless client and a base station (or access point). 802.11 supports both portable and mobile stations. While portable station can be moved from location to location, it is generally used from a fixed location (for example a laptop in the office). The mobile station accesses the WLAN while it is in motion (for example a user accessing a PDA while he or she is walking). The 802.11 specifications have defined different physical media - the radio-based physical 802.11b media operates at 2.4 GHz ISM band. 802.11b can provide bandwidths up to 11 Mbps at a distance of 50 to 150 feet indoors to over 1000 feet (with line of sight) outdoor. Hardware support is already available for Windows, various UNIX flavors, Macintosh (AirPort interface). 802.11a is the implementation of physical layer at 5 GHz UNII (Unlicensed National Information Infrastructure) in the USA. 802.11a operates up to 54 Mbps. However, due to power limits, the access points offer access only within a few dozen feet. This is particularly suitable for home use where high bandwidth applications e.g. DVD, video-on-demand, digital TV, HDTV etc. are typically deployed. The commercial hardware supporting this standard is likely to roll out by end of 2001. Although the 802.11a and 802.11b standards were established concurrently, 802.11b was first to market due to its simpler technical implementation. However, 802.11a, offering significant performance advantages, is now available ...

Is Freudian theory falsifiable (by Popper's criteria) Essay

Is Freudian theory falsifiable (by Popper's criteria) - Essay Example The matter is the fact that at those times there was a strong belief that works of these scientists are absolutely scientific. But Popper had different point of view. According to him Einstein’s theory was distinguished from theories of Freud, Adler and Marx due to its openness to be falsifiable, i.e. to criticism. Popper considered that Freud, Marx, and Adler gave some true and important issues, despite he thought their theories to be unscientific. In general our intellectual culture has been largely influenced by Popper’s criticism of Freudian theory and his castigation of inductivism. Thus, Frederick Crews, the literary critic states that Popper has proved his own denial of Freudian explanations and Peter Medawar, biologists, has approved both of Karl Popper’s complaints with gusto. In 1935 in the philosophical analysis of the scientific method Karl Popper represented his famous criterion of falsifiability, which is now considered to be an important concept of science as well as of philosophy of science. According to this criterion any theory, proposition or hypothesis can be considered â€Å"scientific† only when it is falsifiable. Thus, Popper’s criterion is necessary but not sufficient for evaluation of any ideas claiming to be scientific (Sokal, 1998). Any theory satisfies Popper’s criterion (i.e. it is falsifiable and therefore scientific) in the event that there is a methodological opportunity to refute it by setting one or another experiment, even if such an experiment has not yet been delivered. According to this criterion, a statement, or system of statements contain information about the empirical world only if it is able to come into collision with the experience, or more accurately - if it can be systematically checked, that is subjected to (according to some â€Å"methodological solutions†) checks, which may result in its denial. In other words, according to Popper's criterion, a scientific theory cannot be fundamentally unassailable. Thus, according to this doctrine, the problem of demarcation (i.e. separation of scientific knowledge from the unscientific) is solved. Popper called this unequal "power" and role in the verification of meaning and truth of scientific theories inherent in confirming and refuting factors â€Å"cognitive asymmetry†. Based on this â€Å"asymmetry† Popper proclaimed the replacement of the â€Å"principle of verification† (i.e. a positive or confirmed check), used by logical empiricists, with the principle of â€Å"falsification† (that is the principle of reliable denial). It means that the verification of scientific essence, and then of the truth of scientific theories must be carried out not through their confirmation, but mainly (or exclusively) through their denial. Popper's criterion requires that a theory or hypothesis should not be fundamentally unassailable. According to Popper a theory cannot be considered scient ific only on the grounds that there is one, several or infinitely many experiments, confirming it. Since almost any theory, formed on the basis of at least some of the experimental data, permits the conducting of a large number of supporting experiments, the existence of confirmation cannot be considered a token of scientific theory. According to Popper, theories differ with respect to the possibility of setting up an experiment able, at least in principle, give a