deodatabase

Monday, March 24, 2008

Transport Layer Security (TLS)

The TLS protocol allows applications to communicate across a network in a way designed to prevent eavesdropping, tampering, and message forgery. TLS provides endpoint authentication and communications privacy over the Internet using cryptography. Typically, only the server is authenticated (i.e., its identity is ensured) while the client remains unauthenticated; this means that the end user (whether an individual or an application, such as a Web browser) can be sure with whom they are communicating. The next level of security—in which both ends of the "conversation" are sure with whom they are communicating—is known as mutual authentication.

Monday, March 17, 2008

Hybrid electric vehicle (HEV)

A hybrid electric vehicle (HEV) is a vehicle which combines a conventional propulsion system with an on-board rechargeable energy storage system (RESS) to achieve better fuel economy than a conventional vehicle without being hampered by range from a charging unit like a battery electric vehicle, which uses batteries charged by an external source. The different propulsion power systems may have common subsystems or components.

Regular HEVs most commonly use an internal combustion engine (ICE) and electric batteries to power electric motors. Modern mass produced HEVs prolong the charge on their batteries by capturing kinetic energy via regenerative braking, and some HEVs can use the combustion engine to generate electricity by spinning an electrical generator (often a motor-generator) to either recharge the battery or directly feed power to an electric motor that drives the vehicle.

Sunday, March 09, 2008

Transreflective liquid crystal display

A transreflective liquid crystal display is a liquid crystal display (LCD) that reflects most of the sunlight it is exposed to, and automatically increases or decreases the light emanating from the screen depending on how much light shines on it. Therefore, it reduces the need for manual light adjustment of the screen.

Transreflective liquid crystal displays use a retroreflector to transmit light when external sources of light are available, such as the sun or a lamp, and illuminate the screen well. When these sources are available but do not illuminate well, the display transmits its own light from a backlight at the rear of the display.

Tuesday, March 04, 2008

Ethnopharmacology

When studying the effectiveness of herbal medicines and other nature-derived remedies, the information of the traditional uses of certain extracts of even extract combinations plays a key role. The lack of studies proving the use of herbs in traditional care is especially an issue in the United States where the use of herbal medicine has fallen out of use since the Second World War and was considered suspect since the Flexner Report of 1910 led to the closing of the eclectic medical schools where botanical medicine was exclusively practiced. This is further complicated by most herbal studies in the latter part of the 20th Century having been published in languages other than English such as German, Dutch, Chinese, Japanese, Korean and Farsi.