Modeling+and+Simulations

Modeling and Simulations

[|The difference between a model and a simulation]

[|Pilots train without taking off]

[|Models' projections for Flu miss mark by wide margin] [|Recipe for disaster: the formula that killed Wall Street]

[|Met Office forecasts a supercomputer with a huge carbon footprint]

[|Car crash testing - Is it accurate?]

[|Traffic Control Simulation]

[|Dynamic Population Pyramid for the USA]

[|Computer Simulations - Modeling the future] [|War Simulator Unveiled] [|Computer Simulation has Taiwan beating China in War]

=__**Mapping**__=

What is GPS?
The Global Positioning System (GPS) is a U.S.-owned utility that provides users with positioning, navigation, and timing (PNT) services. This system consists of three segments: the space segment, the control segment, and the user segment. The U.S. Air Force develops, maintains, and operates the space and control segments.
 * The space segment consists of a nominal constellation of 24 operating satellites that transmit one-way signals that give the current GPS satellite position and time.
 * The control segment consists of worldwide monitor and control stations that maintain the satellites in their proper orbits through occasional command maneuvers, and adjust the satellite clocks. It tracks the GPS satellites, uploads updated navigational data, and maintains health and status of the satellite constellation.
 * The user segment consists of the GPS receiver equipment, which receives the signals from the GPS satellites and uses the transmitted information to calculate the user’s three-dimensional position and time.

GPS Services
GPS satellites provide service to civilian and military users. The civilian service is freely available to all users on a continuous, worldwide basis. The military service is available to U.S. and allied armed forces as well as approved Government agencies. A variety of GPS augmentation systems and techniques are available to enhance system performance to meet specific user requirements. These improve signal availability, accuracy, and integrity, allowing even better performance than is possible using the basic GPS civilian service. The outstanding performance of GPS over many years has earned the confidence of millions of civil users worldwide. It has proven its dependability in the past and promises to be of benefit to users, throughout the world, far into the future.

Some of the advantages of GPS are: -
 * Technology extends human faculties and makes work easier thank to the IT systems involved. Memory, accuracy and speed are great advantages
 * Accurate
 * Easy to store
 * Can be viewed all around the world
 * Can be viewed at all GPS's/computers
 * Breaks down distance barriers-easy to transfer data

[|Advantages of GPS Technology] [|GPS to help the blind] [|Using GPS to track animals] [|The Pros and Cons of Using GPS to track Teens]

Some of the issues and disadvantages with GPS are: -


 * Operation of the hardware and design of the software. Correspondence of data with the real world. Data have to be updated, otherwise they become outdated, therefore unreliable. Maps on GPS devices are not updated in real time for all models. This means that it is possible a GPS device will direct you onto a road that is closed or no longer exists. It could also miss new roads and businesses.
 * If data are input incorrectly, the entire design becomes unreliable. The correspondence and creation of data. If someone changes the data in the software, the whole design would become unreliable.
 * Time consuming to create
 * High technology needed
 * Reliability on technology. GPS devices are limited by having clear access to the satellites that provide the tracking. In locations with tall buildings or sparse coverage, reception can be poor. Turn-by-turn directions are not available on every type of __GPS device __ Some will give very little advanced notice before an upcoming turn. GPS units that are not plugged into a power source, and rely on batteries, which can drain quickly. This can increase the cost of owning a GPS unit significantly.
 * Need for restricted access to some machines. The GPS is a very valued system, which can be easily abused if being stolen by the terrorists.
 * Costly. Purchasing a GPS based on price can be a major disadvantage. If you purchase a "bargain GPS," you will get what you pay for, and features such as traffic and up-to-date maps could be lacking.

[|Problems with GPS units] [|Satellite glitch rekindlesn GPS concerns]

The Future of GPS
The United States is committed to an extensive modernization program, including the implementation of a second and a third civil signal on GPS satellites. The second civil signal will improve the accuracy of the civilian service and supports some safety-of-life applications. The third signal will further enhance civilian capability and is primarily designed for safety-of-life applications, such as aviation.

[|The Rise of GPS Mobile Devices] [|Move over GPS, here comes the smartphone] [|GPS units with more to say]