| Ernest Shackleton (15 February 1874 – 5 January 1922) led three British expeditions to the Antarctic during the Heroic Age of Antarctic Exploration. He and three companions established a new record Farthest South latitude, 112 miles (180 km) from the South Pole, as part of the Nimrod Expedition of 1907–1909, and Shackleton was knighted on his return home. He planned the Imperial Trans-Antarctic Expedition of 1914–1917 but his ship, Endurance, became trapped in pack ice and then sank on 21 November 1915. The crew escaped and used the lifeboats to reach Elephant Island and ultimately the island of South Georgia in a stormy ocean voyage of more than 700 nautical miles (800 mi; 1,300 km), Shackleton's most famous exploit. He returned to the Antarctic in 1921 with the Shackleton–Rowett Expedition, but died of a heart attack on South Georgia; at his wife's request, he was buried there. In the latter part of the 20th century, Shackleton became a role model for leadership in extreme circumstances.Ernest Shackleton (15 February 1874 – 5 January 1922) led three British expeditions to the Antarctic during the Heroic Age of Antarctic Exploration. He and three companions established a new record Farthest South latitude, 112 miles (180 km) from the South Pole, as part of the Nimrod Expedition of 1907–1909, and Shackleton was knighted on his return home. He planned the Imperial Trans-Antarctic Expedition of 1914–1917 but his ship, Endurance, became trapped in pack ice and then sank on 21 November 1915. The crew escaped and used the lifeboats to reach Elephant Island and ultimately the island of South Georgia in a stormy ocean voyage of more than 700 nautical miles (800 mi; 1,300 km), Shackleton's most famous exploit. He returned to the Antarctic in 1921 with the Shackleton–Rowett Expedition, but died of a heart attack on South Georgia; at his wife's request, he was buried there. In the latter part of the 20th century, Shackleton became a role model for leadership in extreme circumstances. | |
| Leland D. Melvin (born February 15, 1964) is an American engineer and retired NASA astronaut. He served on board the Space Shuttle Atlantis as a mission specialist on STS-122, and as mission specialist 1 on STS-129, logging more than 565 cumulative hours in space. He was named NASA's associate administrator for education in 2010 and retired from the agency in 2014. This official NASA portrait of Melvin wearing an orange Advanced Crew Escape Suit was taken in 2009. | |
| Both the geographic and magnetic South Poles were reached for the first time during the Heroic Age. The achievement of being first to the geographical pole was the primary object in many expeditions, as well as the sole rationale for Roald Amundsen's venture, which became the first to reach it in 1911. Other expeditions aimed for different objectives in different areas of the continent. As a result of all this activity, much of the continent's coastline was discovered and mapped, and significant areas of its interior were explored. The expeditions also generated large quantities of scientific data across a wide range of disciplines, the examination and analysis of which would keep the world's scientific communities busy for decades. | |
| Exploration of the southernmost part of the globe had been an off-and-on area of interest for centuries prior to the Heroic Age, yet the sheer isolation of the region as well as its inhospitable climate and treacherous seas presented enormous practical difficulties for early maritime technology. About a century after the Age of Exploration, British explorer James Cook became one of the first explorers known to have traveled to the region. The discoveries of his second voyage (1772–1775) changed the world map forever. | |
| Prior to this expedition it was believed that a large continent known as Terra Australis occupied the majority of the Southern Hemisphere. Cook discovered that no such landmass existed, though massive ice floes prevented his reaching Antarctica proper. | |
| As Europe settled after a period of war and unrest, explorers Fabian Gottlieb von Bellingshausen, John Biscoe, John Balleny, Charles Wilkes, Jules Dumont d'Urville, and James Clark Ross sought greater knowledge of the Antarctic regions. | |
| Synthesized speech can be created by concatenating pieces of recorded speech that are stored in a database. Systems differ in the size of the stored speech units; a system that stores phones or diphones provides the largest output range, but may lack clarity. For specific usage domains, the storage of entire words or sentences allows for high-quality output. Alternatively, a synthesizer can incorporate a model of the vocal tract and other human voice characteristics to create a completely "synthetic" voice output. | |
| The quality of a speech synthesizer is judged by its similarity to the human voice and by its ability to be understood clearly. An intelligible text-to-speech program allows people with visual impairments or reading disabilities to listen to written words on a home computer. Many computer operating systems have included speech synthesizers since the early 1990s. | |
| The process of assigning phonetic transcriptions to words is called text-to-phoneme or grapheme-to-phoneme conversion. Phonetic transcriptions and prosody information together make up the symbolic linguistic representation that is output by the front-end. The back-end—often referred to as the synthesizer—then converts the symbolic linguistic representation into sound. In certain systems, this part includes the computation of the target prosody (pitch contour, phoneme durations) | |
| Long before the invention of electronic signal processing, some people tried to build machines to emulate human speech. Some early legends of the existence of "Brazen Heads" involved Pope Silvester II (d. 1003 AD), Albertus Magnus (1198–1280), and Roger Bacon (1214–1294). |