Monday, April 30, 2007

Traffic psychology

Traffic psychology is a young escalating field in psychology. Whereas traffic psychology is first and foremost related to "the study of the behavior of road users and the psychological processes underlying that behavior" as well as to the relation between behavior and accidents, transportation psychology, sometimes referred to as mobility psychology, has its focus on mobility issues, individual and social factors in the movement of people and goods, and travel demand management.
There is no single theoretical framework in traffic psychology, but many specific models explaining, e.g., perceptual, intentional, cognitive, social, motivational and emotional determinants of mobility and traffic behavior. One of the most well-known behavioral models divides the various tasks occupied in traffic participation into three hierarchical levels, i.e. the strategic, the tactical and the operational level. The model demonstrates the diversity of decision and control tasks which have to be accomplished when driving a vehicle. However, until now, most of the psychological models have a rather heuristic nature, e.g. risk theories like the risk compensation hypothesis, Fuller's task capability model, and thus are not sufficiently precise to allow for concrete behavioral prediction and control. This is partly due to the importance of individual differences, a major topic of psychology which in traffic and transportation has not yet been adequately accounted for. On the other hand, social-psychological attitude-behavior models, such as Ajzen's theory of planned behavior, have been helpful in identifying determinants of mobility decisions.

Tuesday, April 24, 2007

Wood

Wood is the xylem tissue of woody plants, particularly trees but also shrubs. Wood from the latter is only formed in small sizes, reducing the diversity of uses. Wood is a hygroscopic, cellular and anisotropic material. Dry wood is composed of fibers of cellulose (40%–50%) and hemicellulose (20%–30%) held together by lignin (25%–30%).
Artists can use wood to create delicate sculptures.Wood has been used by man for millenia for many purposes, being many things to many people. One of its primary uses is as fuel. It may also be used as a material, for making artworks, boats, buildings, furniture, ships, tools, weapons, etc. Wood has been an important construction material since humans began building shelters, and remains in plentiful use today. Construction wood is usually known as timber in International English, and lumber in American English. Wood may be broken down and be made into chipboard, engineered wood, hardboard, medium-density fibreboard, oriented strand board, paper or used to make other synthetic substances.

Wednesday, April 18, 2007

Microphone

A microphone, sometimes called a mic (pronounced "mike"), is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, tape recorders, hearing aids, motion picture production and in radio and television broadcasting.
The invention of a practical microphone was crucial to the early development of the telephone system. Emile Berliner made-up the first microphone on March 4, 1877, but the first helpful microphone was invented by Alexander Graham Bell. Many early developments in microphone design took place in Bell Laboratories.
In all microphones, sound waves (sound pressure) are translated into mechanical vibrations in a thin, flexible diaphragm. These sound vibrations are then converted by various methods into an electrical signal which varies in voltage amplitude and frequency in an analog of the original sound. For this reason, a microphone is an acoustic wave to voltage modulation transducer.

Tuesday, April 10, 2007

Smartphone

A smartphone is any electronic handheld device that integrates the functionality of a mobile phone, personal digital assistant or other information appliance. This is often achieved by adding telephone functions to an existing PDA or putting "smart" capabilities, such as PDA functions, into a mobile phone. A key characteristic of a smartphone is that additional applications can be installed on the device. The applications can be developed by the manufacturer of the handheld device, by the operator or by any other third-party software developer.
It is more and more difficult to define exactly what qualifies as a smartphone. almost all new mobile phones have some rudimentary PDA functionality such as phonebooks, calendars, and task lists. Furthermore, BREW and Java ME devices allow for the installation of extra applications but are still not measured smartphones. There are many BREW devices with PDA functionality, the ability to run third-party applications in native code and sporting displays as large as 240x320 pixels; yet they are not considered smartphones. The elusive definition seems loosely tied to the particular operating systems listed below.
The first smartphone was called Simon intended by IBM in 1992 and shown as a idea product at COMDEX. It was free to the public in 1993 and sold by BellSouth. Besides a mobile phone, it also contained a calendar, address book, world clock, calculator, note pad, e-mail, and games. Customers could also use a stylus to write straight on its screen to create facsimiles and memos.

Friday, April 06, 2007

Electronic mixer

An elepctronic mixer is a device for addition two or more electronic signals. There are two basic types of mixer. Additive mixers add two signals together, and are used for such applications as audio mixing. Multiplying mixers multiply the signals together, and create an output containing both original signals, and new signals that have the sum and dissimilarity of the frequency of the original signals.Additive mixers are typically resistor networks, surrounded by impedance matching and amplification stages.Multiplying mixers have been done in a wide range of ways. The most popular are diode mixers, gilbert cell mixers, diode ring mixers and switching mixers.

Monday, April 02, 2007

Pace Car

A pace car has been used to start the Indianapolis 500 since 1911. The first pace car was a Stoddard-Dayton driven by Carl G Fisher. Other car and motorcycle races have also used pace cars.The purpose of a pace car is to help provide an organized running start to the race.The racecars follow the pace car around the track, maintaining their assigned pole positions.The exact details can vary, but characteristically, there is one "parade lap" at a relatively low speed. This is followed by a much faster lap that straight leads to the formal start of the race, as the pace car turns off the track into the pit area.Many years, the driver of the pace car is someone associated to car racing or the automotive industry, such as the dealer that provided the car, an executive of a US automaker, or a retired racecar driver. However, particularly in recent years, the driver may be a celebrity; recently comedian and talk show host Jay Leno , and actor Anthony Edwards have driven the Indy pace car. Colin Powell was selected to drive the pace car for the 2005 event.