PROJECT OVERVIEW PART ONE PART TWO PART THREE |
Technologies
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Part I: Technologies (3/3) Technology Overview The History of Two-way Radio Communication The army also used two way radio communications in its program known as MARS (Military Affiliate Radio System). The programs were operated by the Army, Navy, and Marine Corp. The members of MARS are volunteer licensed amateur radio operators. They were originally known as the AARS, or Army Amateur Radio System, from 1925-1946. During the US entry in World War II, the AARS was suspended, but was reactivated by 1946 and renamed MARS, which it is called to this day. The main concept of MARS is to provide auxiliary and emergency communications for local, national, and international use. One man who was responsible for much of this new radio-communication technology was Daniel Noble, who joined Motorola as the Director of Research in 1940. He designed complete FM mobile and portable communications equipment. Noble was also directly responsible for the development of the U.S. Army SCR-300 Walkie Talkie, used in combat, and also created the first practical two-way FM radio telephone mobile system. World War II also stimulated the increase of FM manufacturing capacity, which eliminated background static and reduced the need for high transmission power. The military currently uses MARS as a form of two way radio communication. It also uses the mobile subscriber equipment (MSE), which the U.S. Army's mobile telephone system for the battlefield, designed to work as a cellular phone. Besides being used by the army, the two-way radio has also been used by citizens, known as the Citizen’s Band (CB) Radio Service. Mobile CB operation is used in different automotive vehicles. Most CB operation occurs at frequencies near 27 mHz and have proven useful in disaster situations, like floods and earthquakes. The Radio Emergency Associated Communications Team (REACT) provides communication support in emergencies and is recognized as the premier CB emergency channel in the United States. Much of this has lead to the most current form of two way communication: the cellular telephone system, created by Bell Laboratories in the 1970’s. Cellular telephone communication splits the geographical area into non-overlapping, hexagonal shaped cells. Each cell has a base station (its own transmitter and receiver) to communicate with the mobile units in that cell as well as a switching station that coordinates mobile units across cells. In 1983, the FCC (Federal Communications Commission) allocated a block of spectrum for the advanced mobile phone system in Chicago. The AMPS cellular standard uses analog FM and full-duplex radio channels, which has simultaneous transmission and reception. Cellular phones are the most current technology in two way communication. The Silent Sentry system utilizes a low-frequency two way radio for communication between vital workers and relay of vital health information of each worker to a central command center. A low-frequency device is specifically required to maximize range and penetration through buildings and other infrastructure within which first responders will be working. Higher frequency cell phones (especially those in the 1800-1900 MHz spectrum) provide much greater bandwidth than low frequnecy technologies, but at the expense of range. For the purposes of the Silent Sentry, low frequency and maximum range is more important than high bandwidth, as there are relatively little data being passed on by the device. Daniel Noble: MARS: Two-way radio police communication: Citizen’s band Radio service: Overview on wireless communications: History of Devices used to Monitor People’s Health The first blood pressure monitoring device was created by Reverend
Stephen Hales in 1733. Hales made an incision into a horse's artery
and inserted a long glass tube upright into the incision. Pressure
was generated from the pumping action of the heart and the blood
level in the tube rose. This method, known as the Invasive Catheterization
Method, is seldom used today due to its high risks of infection.
More noninvasive techniques are currently employed. Out of this came the Oscillometric Method. This did not use a microphone
and was able to measure the systolic and diastolic pressures as
well as the mean arterial pressure. Pressure data is recorded by
the device, so sound interference as well as cuff placement is not
a major problem. It is able to measure pressure with pressure-sensitive
algorithms. Michael Croslin, the founder of the MedTek Corporation,
invented the computerized blood pressure device called the MedTek
410 in 1978. A very important device that is also used is the respirator. The first mechanical ventilator was developed by Stephen Hales in 1743. It was a manually operated bellow and simply inflated the lungs. The first real respirator was called the "iron lung," invented by Harvard medical researcher, Philip Drinker assisted by Louis Agassiz Shaw in 1927. The inventors used an iron box and two vacuum cleaners. The first users were polio sufferers with chest paralysis. The iron lung exerted a push-pull motion on the chest. This was the standard ventilator for both acute and long-term respiratory support from 1931 to 1956. Respirators are devices that supply oxygen or a mixture of oxygen and carbon dioxide for breathing. Another major monitoring device is the EKG, which is known as the electrocardiogram. The EKG came from a modified galvanometer in 1849, where DuBois-Reymond added a switch so that the galvanometer could measure current. This device was called a "Rheotome” and was then further modified in 1868 by Bernstein, who created the “differential rheotome.” This was used to measure the first EKGs of frog hearts. In 1887, Augustus De'sire' Waller was the first to use the capillary electrometer (created by Lippmann in 1872, due to the lack of sensitivity of the differential rheotome) to record the electrical activity of the human heart. He initially called the record an electrogram, but by 1900, Einthoven introduced the term now used, "electrocardiogram.” Einthoven developed a better “string” galvanometer, but the first EKG machine introduced to the United States was an Edelmann String Electrocardiograph in 1909. Meanwhile, improvements were readily being made on the EKG machine. It was reduced in size, used vacuum tubes for amplification, employed the cathode ray tube, and developed direct-writing instruments. The Silent Sentry will monitor vital signs of workers such as heart rates, oxygen concentration, etc. and transmit the information to a command center using the aforementioned low-frequency radio. History of respirators: Mechanical ventilation: History of EKG machine: History of blood pressure monitoring: History of Tracking Methods Radar was the first large-scale effort to track objects. It was based on the discovery made in 1887 by Heinrich Hertz in Germany that radio waves could be transmitted through some materials while other materials reflected the waves. Throughout the 1920s and 1930s, much research was done based on this finding. The result? Useful radar systems that could be used to navigate ships, guide airplanes, and locate enemy craft in wartime. Radar has since been used in many ways, such as in monitoring precipitation, but tracking has always been at the top of the list. In the 21st century, however, the most effective method of tracking would certainly involve the use of the Global Positioning System (GPS). Originally envisioned in 1973 by the Department of Defense to be used by the military, GPS only reached full operational capacity in 1995. This network of 24 satellites that orbit the Earth and relay information to their ground stations can pinpoint the location of an object on Earth to the nearest meter. This involves a process based on triangulation that uses data from three satellites to locate exactly where an object is. (for more information, visit http://www.trimble.com/gps/how.html) Considering the size of the Earth, the implications of this technology are huge. Anything – or anyone – equipped with a small receiver can be traced anywhere in the world. Already, the relatively new technique of GPS is at use in tracking; Chicago uses it to track emergency vehicles (directing them on the fastest routes), while some Australian taxi companies are using it to track cabs (for profit as well as safety). The possibilities, however, are boundless. GPS can make the smart T-shirt a reality by making it quick and easy to find someone using only a computer. It is one technological innovation that is key to the success of the smart T-shirt. The Silent Sentry uses GPS to track the position of first responders and relay this information back to a central command center so that workers can be efficiently positioned to work and be rescued if their location is compromised. All about GPS: The beginnings of GPS: Press releases about GPS: Implanting ID-chips in humans: History of radar:
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Two-way radio communication
became prevalent in the twentieth century, and has been used by
the police, army, and local citizens. In 1933, the first two-way
AM mobile radio was installed in a police patrol car in Bayonne,
NJ. The radio operated in half duplex mode (a “push-to-talk”
system). Instead of just receiving calls, the patrollers could communicate
with the headquarters by using transmitters. The Bayonne system
was a success, and soon, two way radio communication was being used
in police stations throughout the nation.
Humans have always been
fascinated with keeping track of where things were; sometimes it
has even been a necessity. Neanderthals tracked their prey using
prints left in ground; mothers have kept watch over their children;
scientists trace the location of animals in the wild. Today, radar
and GPS have been the key players in tracking. We have reached the
stage where people can be injected with tiny chips that can identify
them and (if used in conjunction with GPS) keep track of where they
are. 
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