1.
Sonar
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Sonar is a technique that uses sound propagation to navigate, communicate with or detect objects on or under the surface of the water, such as other vessels. Two types of technology share the name sonar, passive sonar is essentially listening for the sound made by vessels, active sonar is emitting pulses of sounds, Sonar may be used as a means of acoustic location and of measurement of the echo characteristics of targets in the water. Acoustic location in air was used before the introduction of radar, Sonar may also be used in air for robot navigation, and SODAR is used for atmospheric investigations. The term sonar is used for the equipment used to generate. The acoustic frequencies used in sonar systems vary from low to extremely high. The study of sound is known as underwater acoustics or hydroacoustics. In the 19th century a bell was used as an ancillary to lighthouses to provide warning of hazards. The use of sound to locate underwater in the same way as bats use sound for aerial navigation seems to have been prompted by the Titanic disaster of 1912. S. Revenue Cutter Miami on the Grand Banks off Newfoundland Canada, in that test, Fessenden demonstrated depth sounding, underwater communications and echo ranging. The so-called Fessenden oscillator, at ca.500 Hz frequency, was unable to determine the bearing of the due to the 3 metre wavelength. The ten Montreal-built British H class submarines launched in 1915 were equipped with a Fessenden oscillator, during World War I the need to detect submarines prompted more research into the use of sound. Although piezoelectric and magnetostrictive transducers later superseded the electrostatic transducers they used, lightweight sound-sensitive plastic film and fibre optics have been used for hydrophones, while Terfenol-D and PMN have been developed for projectors. By 1918, both France and Britain had built prototype active systems, the British tested their ASDIC on HMS Antrim in 1920, and started production in 1922. The 6th Destroyer Flotilla had ASDIC-equipped vessels in 1923, an anti-submarine school, HMS Osprey, and a training flotilla of four vessels were established on Portland in 1924. The US Sonar QB set arrived in 1931, by the outbreak of World War II, the Royal Navy had five sets for different surface ship classes, and others for submarines, incorporated into a complete anti-submarine attack system. The effectiveness of early ASDIC was hamstrung by the use of the charge as an anti-submarine weapon. This required a vessel to pass over a submerged contact before dropping charges over the stern. The hunter was effectively firing blind, during which time a commander could take evasive action
2.
Maritime archaeology
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A specialty within maritime archaeology is nautical archaeology, which studies vessel construction and use. As with archaeology as a whole, maritime archaeology can be practised within the historical, industrial, an associated discipline, and again one that lies within archaeology itself, is underwater archaeology, which studies the past through any submerged remains be they of maritime interest or not. An example from the era would be the remains of submerged settlements or deposits now lying under water despite having been dry land when sea levels were lower. The study of submerged aircraft lost in lakes, rivers or in the sea is an example from the historical, industrial or modern era, many specialist sub-disciplines within the broader maritime and underwater archaeological categories have emerged in recent years. This fact has led to shipwrecks often being described in the media, archaeological material in the sea or in other underwater environments is typically subject to different factors than artifacts on land. However, as with terrestrial archaeology what survives to be investigated by modern archaeologists can often be a fraction of the material originally deposited. There are those in the community who see maritime archaeology as a separate discipline with its own concerns. Others value an integrated approach, stressing that nautical activity has economic and social links to communities on land, all that is required is the mastering of skills specific to the environment in which the work occurs. Before the industrial era, travel by water was often easier than over land, as a result, marine channels, navigable rivers and sea crossings formed the trade routes of historic and ancient civilisations. For example, the Mediterranean Sea was known to the Romans as the sea because the Roman empire spread around its coasts. The historic record as well as the remains of harbours, ships and cargoes, later, nations with a strong maritime culture such as the United Kingdom, the Netherlands, Denmark, Portugal and Spain were able to establish colonies on other continents. Wars were fought at sea over the control of important resources, of late maritime archaeologists have been examining the submerged cultural remains of China, India, Korea and other Asian nations. Saltwater is particularly inimical to iron artefacts including metal shipwrecks, an example of such a collection is the Mary Rose. Where it remains even after the passage of time, the iron or steel hull is often fragile with no remaining metal within the layer of concretion and corrosion products. Even in deep water, commercial activities such as pipe-laying operations, such a wreck is the Mardi Gras shipwreck sunk in the Gulf of Mexico in 4,000 feet of water. The shipwreck lay forgotten at the bottom of the sea until it was discovered in 2002 by an inspection crew working for the Okeanos Gas Gathering Company. Large pipelines can crush sites and render some of their remnants inaccessible as pipe is dropped from the surface to the substrate thousands of feet below. Trawl nets snag and tear superstructures and separate artifacts from their context, the wrecks, and other archaeological sites that have been preserved have generally survived because the dynamic nature of the sea bed can result in artifacts becoming rapidly buried in sediments
3.
Submarine
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A submarine is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability, the term most commonly refers to a large, crewed vessel. It is also used historically or colloquially to refer to remotely operated vehicles and robots, as well as medium-sized or smaller vessels, such as the midget submarine. The noun submarine evolved as a form of submarine boat, by naval tradition, submarines are usually referred to as boats rather than as ships. Although experimental submarines had been built before, submarine design took off during the 19th century, Submarines were first widely used during World War I, and now figure in many navies large and small. Civilian uses for submarines include marine science, salvage, exploration and facility inspection, Submarines can also be modified to perform more specialized functions such as search-and-rescue missions or undersea cable repair. Submarines are also used in tourism, and for undersea archaeology, most large submarines consist of a cylindrical body with hemispherical ends and a vertical structure, usually located amidships, which houses communications and sensing devices as well as periscopes. In modern submarines, this structure is the sail in American usage, a conning tower was a feature of earlier designs, a separate pressure hull above the main body of the boat that allowed the use of shorter periscopes. There is a propeller at the rear, and various hydrodynamic control fins, smaller, deep-diving and specialty submarines may deviate significantly from this traditional layout. Submarines use diving planes and also change the amount of water, Submarines have one of the widest ranges of types and capabilities of any vessel. Submarines can work at greater depths than are survivable or practical for human divers, modern deep-diving submarines derive from the bathyscaphe, which in turn evolved from the diving bell. In 1578, the English mathematician William Bourne recorded in his book Inventions or Devises one of the first plans for an underwater navigation vehicle and its unclear whether he ever carried out his idea. The first submersible of whose construction there exists reliable information was designed and built in 1620 by Cornelis Drebbel and it was propelled by means of oars. By the mid-18th century, over a dozen patents for submarines/submersible boats had been granted in England, in 1747, Nathaniel Symons patented and built the first known working example of the use of a ballast tank for submersion. His design used leather bags that could fill with water to submerge the craft, a mechanism was used to twist the water out of the bags and cause the boat to resurface. In 1749, the Gentlemens Magazine reported that a design had initially been proposed by Giovanni Borelli in 1680. By this point of development, further improvement in design stagnated for over a century, until new industrial technologies for propulsion. The first military submarine was the Turtle, a hand-powered acorn-shaped device designed by the American David Bushnell to accommodate a single person and it was the first verified submarine capable of independent underwater operation and movement, and the first to use screws for propulsion
4.
Light beam
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A light beam or beam of light is a directional projection of light energy radiating from a light source. Sunlight forms a light beam when filtered through media such as clouds, foliage, to artificially produce a light beam, a lamp and a parabolic reflector is used in many lighting devices such as spotlights, car headlights, PAR Cans and LED housings. Light from certain types of laser has the smallest possible beam divergence. From the side, a beam of light is visible if part of the light is scattered by objects, tiny particles like dust, water droplets, hail, snow, or smoke. If there are objects in the light path, then it appears as a continuous beam. In any case, this scattering of light from a beam, flashlight, beam directed by hand Headlight, forward beam, the lamp is mounted in a vehicle, or on the forehead of a person, e. g. The difference between the two is that the fog itself is also a visual effect, Laser lighting display- Laser beams are often used for visual effects, often in combination with music. This also used to be done for movie premieres, the waving searchlight beams are still to be seen as an element in the logo of the 20th Century Fox movie studio
5.
Estonia
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Estonia, officially the Republic of Estonia, is a country in the Baltic region of Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia, across the Baltic Sea lies Sweden in the west and Finland in the north. The territory of Estonia consists of a mainland and 2,222 islands and islets in the Baltic Sea, covering 45,339 km2 of land and water, and is influenced by a humid continental climate. The territory of Estonia has been inhabited since at least 6500 BC, in 1988, during the Singing Revolution, the Estonian Supreme Soviet issued the Estonian Sovereignty Declaration in defiance of Soviet rule, and independence was restored on 20 August 1991. Estonia is a parliamentary republic divided into fifteen counties. Its capital and largest city is Tallinn, with a population of 1.3 million, it is one of the least-populous member states of the European Union, Eurozone, North Atlantic Treaty Organization, OECD and Schengen Area. Estonia is a country with an advanced, high-income economy that is among the fastest growing in the EU. Its Human Development Index ranks very highly, and it performs favourably in measurements of economic freedom, civil liberties, the 2015 PISA test places Estonian high school students 3rd in the world, behind Singapore and Japan. Citizens of Estonia are provided with health care, free education. Since independence the country has developed its IT sector, becoming one of the worlds most digitally advanced societies. In 2005 Estonia became the first nation to hold elections over the Internet, in the Estonian language, the oldest known endonym of the Estonians was maarahvas, meaning country people or people of the land. The land inhabited by Estonians was called Maavald meaning Country Parish or Land Parish, one hypothesis regarding the modern name of Estonia is that it originated from the Aesti, a people described by the Roman historian Tacitus in his Germania. The historic Aesti were allegedly Baltic people, whereas the modern Estonians are Finno-Ugric, the geographical areas between Aesti and Estonia do not match, with Aesti being further down south. Ancient Scandinavian sagas refer to a land called Eistland, as the country is called in Icelandic. Early Latin and other ancient versions of the name are Estia and Hestia, esthonia was a common alternative English spelling prior to 1921. Human settlement in Estonia became possible 13,000 to 11,000 years ago, the oldest known settlement in Estonia is the Pulli settlement, which was on the banks of the river Pärnu, near the town of Sindi, in south-western Estonia. According to radiocarbon dating it was settled around 11,000 years ago, the earliest human inhabitation during the Mesolithic period is connected to Kunda culture, which is named after the town of Kunda in northern Estonia. At that time the country was covered with forests, and people lived in communities near bodies of water
6.
Hard disk drive
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The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces. Data is accessed in a manner, meaning that individual blocks of data can be stored or retrieved in any order. HDDs are a type of storage, retaining stored data even when powered off. Introduced by IBM in 1956, HDDs became the dominant secondary storage device for computers by the early 1960s. Continuously improved, HDDs have maintained this position into the era of servers. More than 200 companies have produced HDDs historically, though after extensive industry consolidation most current units are manufactured by Seagate, Toshiba, as of 2016, HDD production is growing, although unit shipments and sales revenues are declining. While SSDs have higher cost per bit, SSDs are replacing HDDs where speed, power consumption, small size, the primary characteristics of an HDD are its capacity and performance. Capacity is specified in unit prefixes corresponding to powers of 1000, the two most common form factors for modern HDDs are 3. 5-inch, for desktop computers, and 2. 5-inch, primarily for laptops. HDDs are connected to systems by standard interface cables such as PATA, SATA, Hard disk drives were introduced in 1956, as data storage for an IBM real-time transaction processing computer and were developed for use with general-purpose mainframe and minicomputers. The first IBM drive, the 350 RAMAC in 1956, was approximately the size of two medium-sized refrigerators and stored five million six-bit characters on a stack of 50 disks. In 1962 the IBM350 RAMAC disk storage unit was superseded by the IBM1301 disk storage unit, cylinder-mode read/write operations were supported, and the heads flew about 250 micro-inches above the platter surface. Motion of the head array depended upon a binary system of hydraulic actuators which assured repeatable positioning. The 1301 cabinet was about the size of three home refrigerators placed side by side, storing the equivalent of about 21 million eight-bit bytes, access time was about a quarter of a second. Also in 1962, IBM introduced the model 1311 disk drive, users could buy additional packs and interchange them as needed, much like reels of magnetic tape. Later models of removable pack drives, from IBM and others, became the norm in most computer installations, non-removable HDDs were called fixed disk drives. Some high-performance HDDs were manufactured with one head per track so that no time was lost physically moving the heads to a track, known as fixed-head or head-per-track disk drives they were very expensive and are no longer in production. In 1973, IBM introduced a new type of HDD code-named Winchester and its primary distinguishing feature was that the disk heads were not withdrawn completely from the stack of disk platters when the drive was powered down. Instead, the heads were allowed to land on an area of the disk surface upon spin-down
7.
Solid-state drive
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A solid-state drive is a solid-state storage device that uses integrated circuit assemblies as memory to store data persistently. SSD technology primarily uses electronic interfaces compatible with traditional block input/output hard disk drives, additionally, new I/O interfaces like SATA Express and M.2 have been designed to address specific requirements of the SSD technology. SSDs have no moving mechanical components and this distinguishes them from traditional electromechanical magnetic disks such as hard disk drives or floppy disks, which contain spinning disks and movable read/write heads. Compared with electromechanical disks, SSDs are typically resistant to physical shock, run silently. However, while the price of SSDs has continued to decline over time, as of 2015, most SSDs use MLC NAND-based flash memory, which is a type of non-volatile memory that retains data when power is lost. For applications requiring fast access but not necessarily data persistence after power loss, such devices may employ batteries as integrated power sources to retain data for a certain amount of time after external power is lost. SSDs had origins in the 1950s with two similar technologies, magnetic core memory and charged capacitor read-only storage and these auxiliary memory units emerged during the era of vacuum-tube computers, though their use ceased with the introduction of cheaper drum storage units. Later, in the 1970s and 1980s, SSDs were implemented in memory for early supercomputers of IBM, Amdahl, and Cray. In the late 1970s, General Instruments produced an electrically alterable ROM which operated somewhat like the later NAND flash memory, unfortunately, a ten-year life was not achievable and many companies abandoned the technology. In 1976, Dataram started selling a product called Bulk Core, in 1978, Texas Memory Systems introduced a 16 kilobyte RAM solid-state drive to be used by oil companies for seismic data acquisition. The following year, StorageTek developed the first RAM solid-state drive, the Sharp PC-5000, introduced in 1983, used 128-kilobyte solid-state storage cartridges containing bubble memory. In 1984, Tallgrass Technologies Corporation had a backup unit of 40 MB with a solid state 20 MB unit built in. The 20 MB unit could be used instead of a hard drive, in September 1986, Santa Clara Systems introduced BatRam, a 4 megabyte mass storage system expandable to 20 MB using 4 MB memory modules. The package included a battery to preserve the memory chip contents when the array was not powered. 1987 saw the entry of EMC Corporation into the SSD market, however, by 1993, EMC had exited the SSD market. Software-based RAM disks remain in use as of 2016 because they are an order of faster than other technology, though they consume CPU resources. In 1989, the Psion MC400 laptop included four slots for removable storage in the form of flash-based solid-state disk cards, in 1991, SanDisk Corporation created a 20 MB solid state drive which sold for around $1,000. In 1994, STEC, Inc. bought Cirrus Logics flash controller operation, in 1995, M-Systems introduced flash-based solid-state drives
8.
Mary Rose
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The Mary Rose is a carrack-type warship of the English Tudor navy of King Henry VIII. After serving for 33 years in wars against France, Scotland. While leading the attack on the galleys of a French invasion fleet, she sank in the Solent, the wreck of the Mary Rose was rediscovered in 1971. It was raised in 1982 by the Mary Rose Trust, in one of the most complex, the surviving section of the ship and thousands of recovered artefacts are of immeasurable value as a Tudor-era time capsule. The finds include weapons, sailing equipment, naval supplies and an array of objects used by the crew. Many of the artefacts are unique to the Mary Rose and have provided insights into topics ranging from naval warfare to the history of musical instruments, since the mid-1980s, while undergoing conservation, the remains of the hull have been on display at the Portsmouth Historic Dockyard. An extensive collection of well-preserved artefacts is on display at the nearby Mary Rose Museum, built to display the reconstructed ship and its artefacts. The Mary Rose was one of the largest ships in the English navy through more than three decades of intermittent war and was one of the earliest examples of a sailing warship. She was armed with new types of guns that could fire through the recently invented gun-ports. After being substantially rebuilt in 1536, she was one of the earliest ships that could fire a broadside. Several theories have sought to explain the demise of the Mary Rose, based on records, knowledge of 16th-century shipbuilding. The precise cause of her sinking is unclear, because of conflicting testimonies. In the late 15th century, England was a relatively insignificant state on the periphery of Europe. The great victories against France in the Hundred Years War were in the past, the War of the Roses—the civil war between the houses of York and Lancaster—had ended with Henry VIIs establishment of the House of Tudor, the new ruling dynasty of England. The ambitious naval policies of Henry V were not continued by his successors, the marriage alliance between Anne of Brittany and Charles VIII of France in 1491, and his successor Louis XII in 1499, left England with a weakened strategic position on its southern flank. Despite this, Henry VII managed to maintain a long period of peace. At the onset of the modern period, the great European powers were France. All three became involved in the War of the League of Cambrai in 1508, the conflict was initially aimed at the Republic of Venice but eventually turned against France
9.
Wreck of the RMS Titanic
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The wreck of the RMS Titanic is located about 370 miles south-southeast off the coast of Newfoundland, lying at a depth of about 12,500 feet or about 2.37 miles. The liner sank in April 1912, when it hit an iceberg during her maiden voyage, the wreck lies in two main pieces about a third of a mile apart. The bow is still recognizable and has a great deal of preserved interiors, despite its deterioration. A substantial section of the middle of the ship apart and is scattered in chunks across the sea bed. The bodies of the passengers and crew would have also distributed across the debris field. Exploration of the wreckage found a pair of boots together on the sea floor where a body had lain. Until 1985, the location and condition of the wreck were unknown, the wreck was finally located,13. The key to its discovery was a remotely controlled deep-sea vehicle called Argo. The wreckage is too fragile to be raised because its condition has deteriorated in the century it has remained on the seafloor, many species of marine animals have made Titanic their home, such as rattail fish, spider crabs and brittle starfishes. The Titanic also plays host to communities of metal-eating bacteria. Over the years after her sinking, many impractical, expensive, the project was soon abandoned as impractical as the divers could not even reach a significant fraction of the necessary depth, where the pressure is over 6,000 pounds per square inch. The lack of technology at the time as well as the outbreak of World War I also put off such a project. In later years, numerous proposals were put forward to salvage Titanic, however, all fell afoul of practical and technological difficulties, a lack of funding and, in many cases, a lack of understanding of the physical conditions at the wreck site. Charles Smith, an architect from Denver, proposed in March 1914 to attach electromagnets to a submarine which would be drawn to the wrecks steel hull. Having found its position, more electromagnets would be sent down from a fleet of barges which would winch Titanic to the surface. An estimated cost of $1.5 million and its impracticality meant that the idea was not put into practice, another proposal involved raising Titanic by means of attaching balloons to her hull using electromagnets. Once enough balloons had been attached, the ship would float gently to the surface, again, the idea got no further than the drawing board. The declared objective was to bring the wreck into Liverpool and convert it to a floating museum, the Titanic Salvage Company was established to manage the scheme and a group of businessmen from West Berlin set up an entity called Titanic-Tresor to support it financially
10.
United States Geological Survey
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The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its resources. The organization has four science disciplines, concerning biology, geography, geology. The USGS is a research organization with no regulatory responsibility. The USGS is a bureau of the United States Department of the Interior, the USGS employs approximately 8,670 people and is headquartered in Reston, Virginia. The USGS also has major offices near Lakewood, Colorado, at the Denver Federal Center, the current motto of the USGS, in use since August 1997, is science for a changing world. The agencys previous slogan, adopted on the occasion of its anniversary, was Earth Science in the Public Service. Prompted by a report from the National Academy of Sciences, the USGS was created, by a last-minute amendment and it was charged with the classification of the public lands, and examination of the geological structure, mineral resources, and products of the national domain. This task was driven by the need to inventory the vast lands added to the United States by the Louisiana Purchase in 1803, the legislation also provided that the Hayden, Powell, and Wheeler surveys be discontinued as of June 30,1879. Clarence King, the first director of USGS, assembled the new organization from disparate regional survey agencies, after a short tenure, King was succeeded in the directors chair by John Wesley Powell. Administratively, it is divided into a Headquarters unit and six Regional Units, Other specific programs include, Earthquake Hazards Program monitors earthquake activity worldwide. The National Earthquake Information Center in Golden, Colorado on the campus of the Colorado School of Mines detects the location, the USGS also runs or supports several regional monitoring networks in the United States under the umbrella of the Advanced National Seismic System. The USGS informs authorities, emergency responders, the media, and it also maintains long-term archives of earthquake data for scientific and engineering research. It also conducts and supports research on long-term seismic hazards, USGS has released the UCERF California earthquake forecast. The USGS National Geomagnetism Program monitors the magnetic field at magnetic observatories and distributes magnetometer data in real time, the USGS operates the streamgaging network for the United States, with over 7400 streamgages. Real-time streamflow data are available online, since 1962, the Astrogeology Research Program has been involved in global, lunar, and planetary exploration and mapping. USGS operates a number of related programs, notably the National Streamflow Information Program. USGS Water data is available from their National Water Information System database
11.
United States Patent and Trademark Office
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The USPTO is unique among federal agencies because it operates solely on fees collected by its users, and not on taxpayer dollars. The USPTO is based in Alexandria, Virginia, after a 2005 move from the Crystal City area of neighboring Arlington, the head of the USPTO is Michelle K. Lee. She took up her new role on January 13,2014, on March 13, she formally took office as Director after being nominated by President Barack Obama and confirmed by the U. S. Senate. She formerly served as the Director of the USPTOs Silicon Valley satellite office, the USPTO cooperates with the European Patent Office and the Japan Patent Office as one of the Trilateral Patent Offices. The USPTO mission is to maintain a permanent, interdisciplinary historical record of all U. S. patent applications in order to fulfill objectives outlined in the United States Constitution. The legal basis for the United States patent system is Article 1, Section 8, an additional building in Arlington, Virginia, was opened in 2009. The USPTO was expected by 2014 to open its first ever satellite offices in Detroit, Dallas, Denver, the first satellite office opened in Detroit on July 13,2012. In 2013, due to the sequestration, the satellite office for Silicon Valley. However, renovation and infrastructure updates continued after the sequestration, and the Silicon Valley location is due to open in San Jose City Hall in mid-2015. As of September 30,2009, the end of the U. S. governments fiscal year, of those,6,242 were patent examiners and 388 were trademark examining attorneys, the rest are support staff. They are generally newly graduated scientists and engineers, recruited from universities around the nation. They hold degrees in scientific disciplines, but who do not necessarily hold law degrees. Unlike patent examiners, trademark examiners must be licensed attorneys, all examiners work under a strict, count-based production system. For every application, counts are earned by composing, filing, and mailing a first office action on the merits, the Patent Operations of the office is divided into nine different technology centers that deal with various arts. Prior to 2012, decisions of patent examiners may be appealed to the Board of Patent Appeals and Interferences, the United States Supreme Court may ultimately decide on a patent case. Similarly, decisions of trademark examiners may be appealed to the Trademark Trial and Appeal Board, with subsequent appeals directed to the Federal Circuit, under the America Invents Act, the BPAI was converted to the Patent Trial and Appeal Board or PTAB. In recent years, the USPTO has seen increasing delays between when a patent application is filed and when it issues, to address its workload challenges, the USPTO has undertaken an aggressive program of hiring and recruitment. The USPTO hired 1,193 new patent examiners in Fiscal Year 2006,1,215 new examiners in fiscal 2007, in 2006, USPTO instituted a new training program for patent examiners called the Patent Training Academy
12.
Sonobuoy
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A sonobuoy is a relatively small buoy expendable sonar system that is dropped/ejected from aircraft or ships conducting anti-submarine warfare or underwater acoustic research. The buoys are ejected from aircraft in canisters and deploy upon water impact, the buoy relays acoustic information from its hydrophone via UHF/VHF radio to operators on board the aircraft. With the technological improvement of the submarine in warfare, the need for an effective tracking system was born. Sound Navigation And Ranging was originally developed by the British—who called it ASDIC—in the waning days of World War I, at the time the only way to detect submarines was by listening for them, or visually by chance when they were on the surface recharging their battery banks. Air patrols could spot surfaced submarines and occasionally, when conditions were right, if contact was made, they would follow the submarine while summoning surface ships by radio to attack it. Sonar saw extremely limited use and was tested in the Atlantic Ocean with few naval officers seeing any merit in the system. With the end of World War I came the end to development of sonar in the United States. However, considerable development of ASDIC took place in the United Kingdom, including integration with a plotting table, in 1931, the Coast and Geodetic Survey proposed the replacement of manned station ships with radio-sonobuoys, and placed the new buoys in service beginning in July 1936. These radio-sonobuoys were the ancestors of the sonobuoys that began to appear in the 1940s, the damage inflicted upon the Allies by German U-boats during World War II made the need for sonar a priority. With millions of tons of shipping being sunk in the Atlantic, sonar was installed on a number of ships along with tadar and high-frequency direction finding to detect surfaced submarines. While sonar was a system, it was constantly improved. Modern anti-submarine warfare methods evolved from the techniques devised for the movement of convoys and it was imperative that submarines be detected and neutralized long before the task group came within range of an attack. Aircraft-based submarine detection was the obvious solution, early sonobuoys had limited range, limited battery life and were overwhelmed by the noise of the ocean. They were also limited by the use of human ears to discriminate man-made noises from the oceanic background, however, they demonstrated that the technology was viable. With the development of better hydrophones, the transistor and miniaturization, the sonobuoy went from being an imposing six feet tall, two feet diameter sensor to the compact suite of electronics it is today. The advancement in sonobuoy technology aided the development of such as the P-2 Neptune, S-2 Tracker, S-3B Viking. Sonobuoys are classified into three categories, active, passive and special purpose, active sonobuoys emit sound energy into the water and listen for the returning echo before transmitting information—usually range and bearing—via UHF/VHF radio to a receiving ship or aircraft. The original active sonobuoys pinged continuously after deployment for a period of time
