OscillationOscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulum and alternating current. Oscillations can be used in physics to approximate complex interactions, such as those between atoms.
Ethernet frameIn computer networking, an Ethernet frame is a data link layer protocol data unit and uses the underlying Ethernet physical layer transport mechanisms. In other words, a data unit on an Ethernet link transports an Ethernet frame as its payload. An Ethernet frame is preceded by a preamble and start frame delimiter (SFD), which are both part of the Ethernet packet at the physical layer. Each Ethernet frame starts with an Ethernet header, which contains destination and source MAC addresses as its first two fields.
SouthSouth is one of the cardinal directions or compass points. The direction is the opposite of north and is perpendicular to both east and west. The word south comes from Old English sūþ, from earlier Proto-Germanic *sunþaz ("south"), possibly related to the same Proto-Indo-European root that the word sun derived from.
2G2G is a short notation for second-generation cellular network, a group of technology standards employed for cellular networks. 2G was commercially launched on the GSM standard in Finland by Radiolinja (now part of Elisa Oyj) in 1991. After 2G was launched, the previous mobile wireless network systems were retroactively dubbed 1G. While radio signals on 1G networks are analog, radio signals on 2G networks are digital, though both systems use digital signaling to connect cellular radio towers to the rest of the mobile network system.
NorthNorth is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. North is a noun, adjective, or adverb indicating direction or geography. The word north is related to the Old High German nord, both descending from the Proto-Indo-European unit *ner-, meaning "left; below" as north is to left when facing the rising sun. Similarly, the other cardinal directions are also related to the sun's position.
Hash joinThe hash join is an example of a join algorithm and is used in the implementation of a relational database management system. All variants of hash join algorithms involve building hash tables from the tuples of one or both of the joined relations, and subsequently probing those tables so that only tuples with the same hash code need to be compared for equality in equijoins. Hash joins are typically more efficient than nested loops joins, except when the probe side of the join is very small.
Crank (mechanism)A crank is an arm attached at a right angle to a rotating shaft by which circular motion is imparted to or received from the shaft. When combined with a connecting rod, it can be used to convert circular motion into reciprocating motion, or vice versa. The arm may be a bent portion of the shaft, or a separate arm or disk attached to it. Attached to the end of the crank by a pivot is a rod, usually called a connecting rod (conrod). The term often refers to a human-powered crank which is used to manually turn an axle, as in a bicycle crankset or a brace and bit drill.
WestWest is one of the four cardinal directions or points of the compass. It is the opposite direction from east and is the direction in which the Sun sets on the Earth. The word "west" is a Germanic word passed into some Romance languages (ouest in French, oest in Catalan, ovest in Italian, oeste in Spanish and Portuguese). As in other languages, the word formation stems from the fact that west is the direction of the setting sun in the evening: 'west' derives from the Indo-European root *wes reduced from *wes-pero 'evening, night', cognate with Ancient Greek ἕσπερος hesperos 'evening; evening star; western' and Latin vesper 'evening; west'.
EastEast is one of the four cardinal directions or points of the compass. It is the opposite direction from west and is the direction from which the Sun rises on the Earth. As in other languages, the word is formed from the fact that east is the direction where the Sun rises: east comes from Middle English est, from Old English ēast, which itself comes from the Proto-Germanic *aus-to- or *austra- "east, toward the sunrise", from Proto-Indo-European *aus- "to shine," or "dawn", cognate with Old High German *ōstar "to the east", Latin aurora 'dawn', and Greek ἠώς ēōs 'dawn, east'.
Bicycle frameA bicycle frame is the main component of a bicycle, onto which wheels and other components are fitted. The modern and most common frame design for an upright bicycle is based on the safety bicycle, and consists of two triangles: a main triangle and a paired rear triangle. This is known as the diamond frame. Frames are required to be strong, stiff and light, which they do by combining different materials and shapes. A frameset consists of the frame and fork of a bicycle and sometimes includes the headset and seat post.
