Early years.

Bolt was born on 21 August 1986 to parents Wellesley and Jennifer Bolt in Sherwood Content, a small town in Jamaica. He has a brother, Sadiki, and a sister, Sherine. His parents ran the local grocery store in the rural area, and Bolt spent his time playing cricket and football in the street with his brother, later saying, "When I was young, I didn't really think about anything other than sports." As a child, Bolt attended Waldensia Primary, where he began showing his sprint potential when he ran in his parish's annual national primary school meet. By the age of twelve, Bolt had become the school's fastest runner over the 100 metres distance.  Upon his entry to William Knibb Memorial High School, Bolt continued to focus on other sports, but his cricket coach noticed Bolt's speed on the pitch and urged him to try track and field events. Pablo McNeil, a former Olympic sprint athlete, and Dwayne Jarrett coached Bolt, encouraging him to focus his energy on improving his athletic abilities. The school had a history of success in athletics with past students, including sprinter Michael Green. Bolt won his first annual high school championships medal in 2001; he took the silver medal in the 200 metres with a time of 22.04 seconds. McNeil soon became his primary coach, and the two enjoyed a positive partnership, although McNeil was occasionally frustrated by Bolt's lack of dedication to his training and his penchant for practical jokes.  When Bolt was a boy, he attended Sherwood Content Seventh-day Adventist Church in Trelawny, Jamaica, with his mother. His mother didn't serve pork to him in accordance with Adventist beliefs.

Early competitions.

Performing for Jamaica in his first Caribbean regional event, Bolt clocked a personal best time of 48.28 s in the 400 metres in the 2001 CARIFTA Games, winning a silver medal. The 200 m also yielded a silver, as Bolt finished in 21.81 s.  He made his first appearance on the world stage at the 2001 IAAF World Youth Championships in Debrecen, Hungary. Running in the 200 m event, he failed to qualify for the finals, but he still set a new personal best of 21.73 s. Bolt still did not take athletics or himself too seriously, however, and he took his mischievousness to new heights by hiding in the back of a van when he

Rise to prominence.

The 2002 World Junior Championships were held in front of a home crowd in Kingston, Jamaica, and Bolt was given a chance to prove his credentials on a world stage. By the age of 15, he had grown to tall, and he physically stood out among his peers. He won the 200 m in a time of 20.61 s, which was 0.03 s slower than his personal best of 20.58 s, which he set in the 1st round. Bolt's 200 m win made him the youngest world-junior gold medallist ever. The expectation from the home crowd had made him so nervous that he had put his shoes on the wrong feet, although he realized the mistake before the race began. However, it

Professional athletics career.

2004–2007 Early career.

Under the guidance of new coach Fitz Coleman, Bolt turned professional in 2004, beginning with the CARIFTA Games in Bermuda. He became the first junior sprinter to run the 200 m in under twenty seconds, taking the world junior record outright with a time of 19.93 s. For the second time in the role, he was awarded the Austin Sealy Trophy for the most outstanding athlete of the 2004 CARIFTA Games. A hamstring injury in May ruined Bolt's chances of competing in the 2004 World Junior Championships, but he was still chosen for the Jamaican Olympic squad. Bolt headed to the 2004 Athens Olympics with confidence and a new record on his side. However, he was hampered by a leg injury and was eliminated in the first round of the 200 metres with a disappointing time of 21.05 s. American colleges offered Bolt track scholarships to train in the United States while continuing to represent Jamaica on the international stage, but the teenager from Trelawny refused them all, stating that he was content to stay in

World-record breaker.

The silver medals from the 2007 Osaka World Championships boosted Bolt's desire to sprint, and he took a more serious, more mature stance towards his career. Bolt continued to develop in the 100 m, and he decided to compete in the event at the Jamaica Invitational in Kingston. On 3 May 2008, Bolt ran a time of 9.76 s, with a 1.8 m/s tail wind, improving his personal best from 10.03 s. This was the second-fastest legal performance in the history of the event, second only to compatriot Asafa Powell's 9.74 s record set the previous year in Rieti, Italy. Rival Tyson Gay lauded the performance, especially praising Bolt's form and technique. Michael Johnson observed the race and said that he was shocked at how quickly Bolt had improved over the 100 m distance. The Jamaican surprised even himself with the time, but coach Glen Mills remained confident that there was more to come.  On

2008 Summer Olympics.

Bolt doubled-up with the 100 metres and 200 metres events at the Beijing Summer Olympics. As the new 100 m world-record holder, he was the favourite to win both races. Michael Johnson, the 200 m and 400 m record holder, personally backed the sprinter, saying that he did not believe that a lack of experience would work against him. Bolt qualified for the 100 m final with times of 9.92 s and 9.85 s in the quarter-finals and semi-finals, respectively. In the Olympic 100 m final, Bolt broke new ground, winning in 9.69 s (unofficially 9.683 s) with a reaction time of 0.165 s. This was an improvement upon his own world record, and he was well ahead of second-place finisher Richard Thompson, who finished in 9.89 s. Not only was the record set without a favourable wind (+0.0 m/s), but he also visibly slowed down to celebrate before he finished and his shoelace was untied. Bolt's coach reported that, based upon the speed of Bolt's

After the 2008 Olympics.

At the end of the 2008 athletics season, Bolt competed in the ÅF Golden League, beginning in Weltklasse Zürich. Despite having the slowest start among his competitors in the 100 m race, he still crossed the finishing line in 9.83 s. Even though the time was slower than both his newly set world record and Asafa Powell's track record, it was still among the top-fifteen 100 m finishes by any sprinter to that date. Bolt admitted that he was not running at full strength because he was suffering from a cold, but he concentrated on winning the race and finishing the season in good health. At the Super Grand Prix final in Lausanne, Bolt ran his second-fastest 200 m with a time of 19.63 s, equalling Xavier Carter's track record. However, it was the 100 m final, featuring Asafa Powell, that drew the most interest. Powell had moved closer

2009 Berlin World Championships.

Bolt started the season competing in the 400 metres in order to improve his speed, winning two races and registering 45.54 s in Kingston, and windy conditions gave him his first sub-10 seconds finish of the season in the 100 m in March. In late April Bolt, suffered minor leg injuries in a car crash. However, he quickly recovered following minor surgery and (after cancelling a track meet in Jamaica) he stated that he was fit to compete in the 150 metres street race at the Manchester Great City Games. Bolt won the race in 14.35 s, the fastest time ever recorded for 150 m. Despite not being at full fitness, he

2010 Diamond League and broken streak.

Early on in the 2010 outdoor season, Bolt ran 19.56 seconds in the 200 m in Kingston, Jamaica for the fourth-fastest run of all-time, although he stated that he had no record breaking ambitions for the forthcoming season. He took to the international circuit May with wins in East Asia at the Colorful Daegu Pre-Championships Meeting and then a comfortable win in his 2010 IAAF Diamond League debut at the Shanghai Golden Grand Prix. Bolt made an attempt to break Michael Johnson's best time over the rarely competed 300 metres event at the Golden Spike meeting in Ostrava. He failed to match Johnson's

2011 World Championships.

Bolt went undefeated over 100 m and 200 m in the 2011 season. He began with wins in Rome and Ostrava in May. He ran his first 200 m in over a year in Oslo that June and his time of 19.86 seconds was a world-leading one. Two further 200 m wins came in Paris and Stockholm the following month, as did a 100 m in Monaco, though he was a tenth of a second slower than compatriot Asafa Powell before the world championships.  Considered the favourite to win in the 100 metres at the 2011 World Championships in Daegu, Bolt was eliminated from the final, breaking "ridiculously early" according to the starter in an interview for BBC Sport, and receiving a false start. This proved to be the highest profile disqualification for a false start since the IAAF changed the rules that previously allowed one false start per race. The disqualification caused some to question the new rule, with

2012 Summer Olympics.

Bolt began the 2012 season with a leading 100 m time of 9.82 seconds in May. He defeated Asafa Powell with runs of 9.76 seconds in Rome and 9.79 in Oslo. At the Jamaican Athletics Championships, he lost to Yohan Blake, first in the 200 m and then in the 100 m, with his younger rival setting leading times for the year.  However, at the 2012 London Olympics, he won the 100 metres gold medal with a time of 9.63 seconds, improving upon his own Olympic record and duplicating his gold medal from the 2008 Beijing Olympics. Blake was the silver medallist with a time of 9.75 seconds. Following the race, seventh-place finisher Richard Thompson of Trinidad and Tobago declared "There's no doubt he's the greatest sprinter of all time", while "USA Today" referred to Bolt as a Jamaican "national hero", noting that his victory came just hours before Jamaica was to celebrate the 50th anniversary of its independence from the United Kingdom. With his 2012 win, Bolt became the first man to successfully defend an Olympic sprint title since Carl Lewis in

2013 World Championships.

Bolt failed to record below 10 seconds early season and had his first major 100 m race of 2013 at the Golden Gala in June. He was served an unexpected defeat by Justin Gatlin, with the American winning 9.94 to Bolt's 9.95. Bolt denied the loss was due to a hamstring issue he had early that year and Gatlin responded: "I don't know how many people have beaten Bolt but it's an honour". With Yohan Blake injured, Bolt won the Jamaican 100 m title ahead of Kemar Bailey-Cole and skipped the 200 m, which was won by Warren Weir. Prior to the 2013 World Championships in Athletics, Bolt set world leading times in the sprints, with 9.85 for the 100 m at the London Anniversary Games and 19.73 for the 200 m in Paris.  Bolt regained the title as world's fastest man by winning the World Championships 100 metres in Moscow. In wet conditions, he edged Gatlin by eight hundredths of a second

2014: Injury and Commonwealth Games.

An injury to Bolt's hamstring in March 2014 caused him to miss nine weeks of training. Having recovered from surgery, Bolt competed in the 4 × 100 metres relay of the 2014 Commonwealth Games in Glasgow. Not in peak form Bolt said that he was attending the Games for the fans and to show his progress since the injury. Bolt and his teammates won the 4 ×

2015 Beijing World Championships.

At the start of 2015, he intended to make the 2017 World Championships in Athletics his last major competition before retirement. Upon his return from injury, Bolt appeared a reduced figure at the start of the 2015 season. He ran only two 100 m and three 200 m before the major championship. He opened with 10.12 seconds for the 100 m and 20.20 for the 200 m. He won the 200 m in New York and Ostrava, but his season's best time of 20.13 seconds ranked him 20th in the world going into the championships. Two 100 m runs of 9.87 in July in London showed better form, but in comparison, Justin Gatlin was easily the top ranked sprinter – the American had times of 9.74 and 19.57 seconds, and had already run under 9.8 seconds on four occasions that season. Bolt entered the World Championships to defend his sprint titles but was not the comfortable favourite he had been since 2008.  In the World

2016 Rio Olympics.

Bolt competed sparingly in the 200 m before the Olympics, with a run of 19.89 seconds to win at the London Grand Prix being his sole run of note over that distance. He had four races over 100 m, though only one was in Europe, and his best of 9.88 seconds in Kingston placed him fourth on the world seasonal rankings. As in the previous season, Gatlin appeared to be in better form, having seasonal bests of 9.80 and 19.75 seconds to rank first and second in the sprints. Doping in athletics was a prime topic before the 2016 Rio Olympics, given the banning of the Russian track and field team for state doping, and Bolt commented that he had no problem with doping controls: "I have no issue with being drug-tested...I remember

2017 season.

Bolt took a financial stake in a new Australia-based track and field meeting series – Nitro Athletics. He performed at the inaugural meet in February 2017 and led his team (Bolt All-Stars) to victory. The competition featured variations on traditional track and field events. He committed himself to three further editions.  In 2017, the Jamaican team was stripped of the 2008 Olympics 4×100 metre title due to Nesta Carter's disqualification for doping offences. Bolt, who never failed a dope test, was quoted by the BBC saying that the prospect of having to return the gold was "heartbreaking". The banned substance in Carter's test was identified as methylhexanamine, a nasal decongestant sometimes used in dietary supplements.  At the 2017 World Athletics

Football career.

In an interview with Decca Aitkenhead of "The Guardian" in November 2016, Bolt said he wished to play as a professional footballer after retiring from track and field. He reiterated his desire to play for Manchester United if given a chance and added, "For me, if I could get to play for Manchester United, that would be like a dream come true. Yes, that would be epic."  In 2018, after training with Norwegian side Strømsgodset, Bolt played for the club as a forward in a friendly match against the Norway national under-19 team. He wore the number "9.58" in allusion to his 100 m world record. Bolt wore the same number whilst captaining the World XI during Soccer Aid 2018 at Old Trafford.  On 21 August 2018, on his 32nd birthday,

Personal life.

Bolt expresses a love for dancing and his character is frequently described as laid-back and relaxed. His Jamaican track and field idols include Herb McKenley and former Jamaican 100 m and 200 m world record holder, Don Quarrie. Michael Johnson, the former 200 m world and Olympic record holder, is also held in high esteem by Bolt.  Bolt has the nickname "Lightning Bolt" due to his name and speed. He is Catholic and known for making the sign of the cross before racing competitively, and he wears a Miraculous Medal during his races. His middle name is St. Leo.  In 2010, Bolt also revealed his fondness of music, when he played a reggae DJ set to a crowd in Paris. He is also an avid fan of the "Call of Duty" video game series, saying, "I stay up late [playing the game online], I can't help it."  In his autobiography, Bolt reveals that he has suffered from scoliosis, a condition that has curved his spine to the right and has made his right leg half an inch shorter than his left. A result of this is that his left leg remains on the ground 14 percent longer than his right leg, with left leg striking with 955 lbs of force and right with 1080 lbs. Biomechanics researchers have studied, with no firm conclusions, whether this asymmetry has helped or hurt Bolt in his sprinting career.  He popularised the "lightning bolt" pose, also known as "to di world" or "bolting", which he used both before races and in celebration. The pose consists of extending a slightly raised left arm to the side and the right arm folded across the chest, with both hands have the thumb and index finger outstretched. His performance of the pose during his Olympic and World Championship victories led to widespread copying of the move, from American President Barack Obama to small children. It has been suggested that the pose comes from Jamaican dancehall moves of the period, though Olympic sprint champion Bernard Williams also had performed similar celebration moves earlier that decade.

Family.

On May 17, 2020, Bolt's longtime

Other sports.

Cricket was the first sport to interest Bolt, and he said if he were not a sprinter, he would be a fast bowler instead. As a child, he was a supporter of the Pakistani cricket team and admired the bowling of Waqar Younis. He is also a fan of Indian batsman Sachin Tendulkar, West Indian opener Chris Gayle, and Australian opener Matthew Hayden. During a charity cricket match, Bolt clean-bowled Gayle who was complimentary of Bolt's pace and swing. Bolt also struck a six off Gayle's bowling. Another bowler complimentary of Bolt's pace was former West Indies fast-bowling great Curtly Ambrose.  After talking with Australian cricketer Shane Warne, Bolt suggested that

Biographical film.

A biographical film based on the athletic life of Bolt to win three Olympic gold medals,

Sponsorships and advertising work.

After winning the 200 m title in the 2002 World Junior Championships in Kingston, Bolt signed a sponsorship deal with Puma. To promote Bolt's chase for Olympic glory in the 2008 Summer Olympics in Beijing, China, Puma released a series of videos including Bolt's then-world-record-setting run in Icahn Stadium and his Olympic preparations. After his record-breaking run in New York City, which was preceded by a lightning storm, the press frequently made puns on the Jamaican's name, nicknaming him "Lightning Bolt" and the "Bolt from the blue". During the 2008 Beijing 100 m final, Bolt wore golden Puma Complete Theseus spikes that had "Beijing 100 m Gold" emblazoned across them. Writing of Bolt's performance at the Olympics, "The Associated Press" said: In September 2010, Bolt travelled to Australia where his sponsor Gatorade was holding an event called the "Gatorade Bolt" to find Australia's fastest footballer. The event was held at the Sydney International Athletic Centre and featured football players from rugby league, rugby union,

Entrepreneurship.

Usain Bolt co-founded electric scooter company Bolt Mobility in 2018, created in his namesake. Bolt founded the micromobility company, which provides electric scooters and other yet-to-be released mobility devices, such as the company's upcoming "Bolt Nano". Bolt appeared in Bolt Mobility's debut commercial, released through YouTube and his official Facebook account. Bolt appeared in a number of interviews for the company, alongside CEO Sarah Pishevar Haynes. Bolt made his first public appearance for the company in March 2019, during the company's New York City launch and

Music producer.

In July 2019, Bolt made his debut as a dancehall music producer with the release of the "Olympe Rosé" riddim that featured 5 tracks from Jamaican dancehall artistes: Dexta Daps "Big Moves",

Personal appearances.

Bolt made a cameo appearance in the opening sketch of 13 October 2012 broadcast of "Saturday Night Live", hosted by Christina Applegate. The segment was a parody of the Vice Presidential debate between Joe Biden and Paul Ryan. In the sketch, Taran Killam mimicking Ryan had just lied about running a 2:50 marathon, a sub-4-minute mile

Statistics.

Records.

Bolt's personal best of 9.58 seconds in 2009 in the 100 metres is the fastest ever run. Bolt also holds the second fastest time of 9.63 seconds, the current Olympic record, and set two previous world records in the event. Bolt's personal best of 19.19 s in the 200 metres is the world record. This was recorded at the 2009 World Championships in Athletics in Berlin against a headwind of −0.3 m/s. This performance broke his previous world record in the event, his 19.30 s clocking in winning the 2008 Olympic 200 metres title.  Bolt has been on three world-record-setting Jamaican relay teams. The first record, 37.10 seconds, was set in winning gold at the 2008 Summer Olympics, although

Guinness World Records.

Bolt claimed 19 Guinness World Records, and, after Michael Phelps, holds second

Average and top speeds.

From his record time of 9.58 s for the 100 m sprint, Usain Bolt's average ground speed equates to. However, once his reaction time of 0.148 s is

Season's bests.

"World

Usain St Leo Bolt, (; born 21 August 1986) is a Jamaican former sprinter and widely considered to be the greatest sprinter of all time. He is a world record holder in the 100 metres, 200 metres and 4 × 100 metres relay.

尤塞恩·-{zh-hant:圣李奥;zh-tw:圣利奥;zh-hans:圣利奥;}-·博尔特(英语:Usain St Leo Bolt,,1986年-8月21日),牙买加前男子短跑运动员,男子100米、男子200米以及男子4×100米接力的世界纪录保持者,同时是以上三项赛事的奥运金牌得主。


Properties.

Beryllium fluoride has unique optical properties. In the form of fluoroberyllate glass it has the lowest refractive index for a solid at room temperature of 1.275. It dispersive power is the lowest for a solid at 0.0093, and the non linear coefficient is also the lowest at 2 × 10.

Structure and bonding.

The structure of solid BeF resembles that of cristobalite. Be centers are four coordinate and tetrahedral and the fluoride centers are two-coordinate. The Be-F bond lengths are about 1.54 Å. Analogous to SiO, BeF can also adopt a number of related structures. An analogy also exists between BeF and AlF: both adopt extended structures at mild temperature.

Gas and liquid BeF.

Gaseous beryllium fluoride adopts a linear structure, with a Be-F distance of 143 pm. BeF reaches a vapor pressure of 10 Pa at 686 °C, 100 Pa at 767 °C, 1 kPa at 869 °C, 10 kPa at 999 °C, and 100 kPa at 1172 °C.  'Molecules' of liquid beryllium fluoride have a fluctuating tetrahedral structure. Additionally, the density of liquid BeF decreases near its freezing point, as Be and F ions begin to coordinate more strongly with one another, leading to the expansion of voids between formula units.

Production.

The processing of beryllium ores generates impure Be(OH). This material reacts with ammonium bifluoride to give ammonium tetrafluoroberyllate: Tetrafluoroberyllate is a robust ion, which allows its purification by precipitation of various impurities as their hydroxides. Heating purified (NH)BeF gives the desired product:  In general the reactivity of BeF ions with fluoride are quite analogous to the reactions of SiO with oxides.

Applications.

Reduction of BeF at 1300 °C with magnesium in a graphite crucible provides the most practical route to metallic beryllium:  The chloride is not a useful precursor because of its volatility.

Niche uses.

Beryllium fluoride is used in biochemistry, particularly protein crystallography as a mimic of phosphate. Thus, ADP and beryllium fluoride together tend to bind to ATP sites and inhibit protein action, making it possible to crystallise proteins in the bound state.  Beryllium fluoride forms a basic constituent of the preferred fluoride salt mixture used in liquid-fluoride nuclear reactors. Typically beryllium fluoride is mixed with lithium fluoride to form a base solvent (FLiBe), into which fluorides of uranium and thorium are introduced. Beryllium fluoride is exceptionally chemically stable and LiF/BeF mixtures (FLiBe) have low melting points (360 °C - 459 °C) and the best neutronic properties of fluoride salt combinations appropriate for reactor use. MSRE used two different mixtures in the two cooling circuits.

Safety.

Beryllium compounds are highly toxic. The increased toxicity of beryllium in the presence of fluoride has been noted as early as 1949. The in mice is about 100 mg/kg by ingestion and 1.8 mg/kg by intravenous injection.

Beryllium fluoride is the inorganic compound with the formula BeF. This white solid is the principal precursor for the manufacture of beryllium metal. Its structure resembles that of quartz, but BeF is highly soluble in water.

氟化铍,化学式:BeF,铍的氟化物,白色固体,最重要的金属铍生产原料。


Life and career.

Rydstrom was born in Chicago. He graduated from the University of Southern California School of Cinematic Arts in 1981. He began his career at Skywalker Sound, Northern California in 1983. Offered the job by a college professor, Gary received the opportunity to work with his mentor, "Star Wars" sound designer Ben Burtt.  After gaining invaluable experience as a sound technician in "Indiana Jones and the Temple of Doom", he went on to do sound design for the comedy "Spaceballs". The sound design for "Backdraft", prepared from scratch, would become the precursor for his sound for "". The original sound effects from "Backdraft" are constantly referenced and have been used for numerous other films including "The Lord of the Rings" film trilogy and "Shrek".  Gary won an Academy Award for his work on "Terminator 2: Judgment Day", for which he pioneered techniques still used today for creating realistic sound effects. Rydstrom also worked with "Terminator 2" director James Cameron on a new 5.1 surround mix for the original "Terminator."  Gary's sound work on "Jurassic Park" led to further innovations, as he and his team set out to create dinosaur sounds by mixing together numerous different animal vocalizations to make the audience feel as though giant bellowing prehistoric beasts surrounded them. The Oscar-winning film was the first motion picture to be presented in DTS.  He subsequently went on to work on sound for numerous films including "Titanic", "Saving Private Ryan", "Minority Report" and "Finding Nemo". He won an MPSE lifetime achievement award, and regularly speaks at various sound design forums sharing his extensive knowledge and enthusiasm with aspiring sound design artists.  He made his directorial debut with the Pixar short "Lifted", for which he received his fourteenth Academy Award nomination. It was included in the Animation Show of Shows in 2006. His debut feature film for the studio, "Newt", has been cancelled. He has also directed the Pixar short "Hawaiian Vacation" and the Lucasfilm animated feature "Strange Magic".  Rydstrom has also served as English language director on "Tales From Earthsea", "Arrietty", "From Up on Poppy Hill", and "The Wind Rises", all four films were produced by Japanese animation company Studio Ghibli.

Awards and nominations.

Gary Rydstrom has been nominated for 19 Academy Awards (7 wins), 12 Golden Reel Awards (5 wins), 5 C.A.S Awards (2 wins), and 5 BAFTA Awards (2 wins).

Gary Roger Rydstrom (born June 29, 1959) is an American sound designer and director. He has been nominated for 19 Academy Awards for his work in sound for movies, winning 7.

加里·罗杰·里德斯特罗姆(英语:Gary Roger Rydstrom)是一位美国音效设计师和电影导演他获得了18项奥斯卡金像奖提名,并7次得奖。


History.

In the 16th century, Mactan Island was colonized by Spain. Augustinian friars founded the town of Opon in 1730, and it became a city in 1961. It was renamed after Datu Lapu-Lapu, the island's chieftain, who led the defeat against the Portuguese explorer Ferdinand Magellan in 1521 in the Battle of Mactan, commemorated at the Lapu-Lapu shrine in Punta Engaño, where Magellan led a landing party of 40 men to resupply who were set upon by 1,500 locals and slew their captain and a few other men.  The municipality of Opon was founded by the Augustinian missionaries in 1730. It was ceded to the Jesuits in 1737, and later restored to the Augustinians. When the Philippine Revolution spread to the Visayas in 1896, the people organised themselves into local revolutionary units.  During the Filipino-American War, a military government was established. The continued resistance of the people of Cebu prompted the American government to restore military control over the province on 17 July 1901. In 1905, Opon held its first municipal election, and Pascual dela Serna was elected town president.  Following the outbreak of World War II, the presence of bulk oil storage tanks in Opon made the town an object of Japanese raids a week after the outbreak of WWII in December 1941. The enemy aircraft succeeded in blowing up two of about fourteen oil storage tanks in Opon. A unit of the Kawaguchi Detachment of the Japanese Imperial Forces landed on the east coast of Cebu on 10 April 1942. Later, the resistance movement was organised by Colonel James M. Cushing, leader of the southern and central units, and Harry Fenton of the northern unit of the Cebu Resistance Movement.  During the Battle of the Visayas, Victor II operations of the American Division led by Major General William Arnold landed in Cebu on 26 March 1945, and subsequently liberated the province.  Congressman Manuel A. Zosa, the representative of the Sixth District of Cebu, sponsored the Bill converting the former municipality of Opon into the present day city of Lapu-Lapu. This was the Republic Act 3134, known as the City Charter of Lapu-Lapu, which was signed on 17 June 1961 by Philippine President Carlos P. Garcia. Lapu-Lapu was inaugurated on 31 December 1961, with Mariano Dimataga, the last municipal mayor, as the first city mayor.  As a fast-growing commercial city, some of its commercial and industrial firms are the General Milling Company, one of the largest in the country; the Cebu Shipyard and Engineering Works, pioneered by Dad Cleland; and the oil companies which resumed their operations after the war. Air transportation for the city is served by the Mactan International Airport.  Historically, the city includes the site of the Battle of Mactan. On 1 August 1973, by virtue of Presidential Decree No. 2060, President Ferdinand E. Marcos declared the site of the battle a national shrine; the preservation, restoration and/or reconstruction of which shall be under the supervision and control of the National Historical Commission in collaboration with the Department of Tourism. Mactan is also the birthplace of Leonila Dimataga-Garcia, wife of Carlos P. Garcia, the fourth President of the Republic. Leonila Dimataga-Garcia was a relative of three-term consecutive Lapu-Lapu Citys' late Mayor, Ernest Weigel Jr. wife, who was the richest mayor in Metro Cebu, with a net worth of P57.7 million in the early 2000s.

Barangays.

Lapu-Lapu comprises 30 barangays:

Demographics.

Lapu-Lapu's residents mainly speak Cebuano, the local language. English is also widely spoken and understood, due to the influx of foreign nationals in the city. Due to the large number of resorts and retirement homes in the city, as well as the growing number of ESL schools, the city also hosts a number of Japanese, Korean, and Chinese speakers.

Transportation.

Mactan-Cebu International Airport (MCIA) is located in this city, which is connected to mainland Cebu via the Marcelo Fernan Bridge and Mactan-Mandaue Bridges, as well as the Cebu–Cordova Link Expressway (located in the nearby town of Cordova), over the sea separating the Mactan island from the island of Cebu. The airport is the main gateway to Cebu and Central Visayas, serving international flights to various destinations, especially to Singapore, Macau, Hong Kong, South Korea, Japan, and Taiwan. MCIA is also the second busiest airport in the Philippines, after Ninoy Aquino International Airport in Manila.

', officially the'(; ), or simply known as City, is a highly urbanised city in the region of Central Visayas,. According to the, it has a population of people.

拉普拉普市(又译拉布拉布市;英文:Lapu-Lapu City)是菲律宾宿务省的第一级城市,是以宿务市为中心的宿务大都会的一部分。


Description.

It is a shrub that reaches 1–2 m and grows in hedges or forms thickets. The leaves are pinnate, have 3–5 leaflets, each leaflet 2.5–6 cm long and 1–3 cm broad. In the wild species (sometimes listed as "Rosa chinensis" var. "spontanea"), the flowers have five pink to red petals. The fruit is a red hip 1–2 cm diameter. The strong, stalk-round branches have an almost bare, purplish-brown bark and there may be many to no curved, stocky, flat spines. The alternately arranged leaves are divided into petiole and leaf blade and a total of 5 to 11 inches long.  The petiole and the rhachis are sparsely spiked and glandular-fluffy hairy. The pinnate leaf blades usually have three or five, rarely seven pinna leaflet. The leaflets are at a length of 2.5 to 6 centimeters and a width of 1 to 3 centimeters wide ovate or ovate-oblong with weak-rounded or broad-wedge-shaped base, more or less long tapered upper end and sharply sawn edge. The leaf top is shiny dark green and leaves are almost bare. The stipulesare fused with the petiole on most of their length. The free area of the stipules is rooted, having entire margins with pointed upper end and often glandular-fluffy hairy.

Inflorescence.

The flowering time ranges in China from April to September. Rarely, the flowers are solitary, usually four or five bundles together. The 2.5 to 6 cm long pedicel is hairy almost bald or glandular-fluffy. The one to three bare bracts are linear with a pointed upper end and smooth or glandular margin. The flowers have a mild fragrance.  The hermaphrodite flowers have radial symmetry with a diameter of 4 to 5 centimeters and are divided with double perianth. There are cultivated forms with simple to more or less strongly filled flowers, which are also wild in China and other areas of temperate latitudes. The bald flower cup (hypanthium) is egg-shaped-spherical or pear-shaped. The early dropping sepals are ovate or sometimes foliage-like, simple or lobed with a dished upper end and bald on the underside and hairy on the top shaggy.  The depending on the form five to several or many petals are white over pink to red or purple, obovate with a wedge-shaped base and a polished upper end. There are many stamens present. The free, hairy styluses tower over the petals and are almost as long as the stamens. In China, the rose hips ripen from June to November and turn red. The bald rose hip is egg-shaped or pear-shaped with a diameter of 1 to 2 centimeters.

Cultivation.

Various forms of "Rosa chinensis" have been cultivated in gardens in China for a long time; therefore it is not easy to separate between wild forms and cultivated forms. Many varieties of garden roses have been bred from "Rosa chinensis". The species is extensively cultivated as an ornamental plant, originally in China, and numerous cultivars have been selected which are known as the China roses. It has also been extensively interbred with "Rosa gigantea" to produce "Rosa × odorata" and by further hybridization the tea roses and hybrid tea roses, and is the source of the so-called "rising" varieties, that is to say, with continuous flowering, or blooming in summer.

Varieties.

Three varieties of the species are recognized in the "Flora of China":

Uses.

Cultivars developed from "Rosa chinensis" have been important in the breeding of many modern garden roses by providing the repeat-blooming characteristic, although this is not a feature of the wild species. The many forms of "Rosa chinensis" are also used in many other ways. The young vegetative plant parts, flower buds and flowers are brewed and eaten as a kitchen herb, for example, as a soup. From the rosehips, a thin fleshy layer that surrounds the seeds is eaten raw or cooked. The seed hair must be removed; It has to be handled very carefully. The seed hairs must not get into the mouth and throat. The seeds are a good source of vitamin E. The seeds can be ground and mixed with flour or added to other foods.

Rosa chinensis (), known commonly as the China rose or Chinese rose, alternatively known as Bengal rose or Bengal Crimson or Bengal Beauty is a member of the genus "Rosa" native to Southwest China in Guizhou, Hubei, and Sichuan Provinces. The first publication of "Rosa chinensis" was in 1768 by Nikolaus Joseph von Jacquin in "Observationum Botanicarum", 3, p. 7, p. 55.

月季(学名:'),又名月月红(江苏浙江)、月月花、长春花(吉林长春)、庚申蔷薇,为蔷薇科蔷薇属的一种,原产于中国中部的贵州、湖北、四川等地,现遍布世界各地。


Overview.

The Brandenburg-Liga, previously referred to as the "Verbandsliga Brandenburg", was established in 1990 from thirteen clubs as a highest league for the German state of Brandenburg, which was established after the league in October 1990, and the Brandenburg Football Association, FLB (German: "Fußball-Landesverband Brandenburg"). It comprised the area of the three Bezirksligas of Potsdam, Frankfurt (Oder) and Cottbus. Each of those three Bezirke contributed four clubs to the new league, with one club coming from the "2nd Division". The Verbandsliga was established within the East German football league system and incorporated in the league system of the united Germany after the end of its first season, in 1991.  The league was (and still is) a feeder league to the NOFV-Oberliga Nord, together with the Berlin-Liga and Verbandsliga Mecklenburg-Vorpommern, which its champion is directly promoted to. As such, it was the fourth tier of the German league system.  The Brandenburg Football Association itself was formed on 28 July 1990.  The league expanded to sixteen clubs in its second season and this number remained as the preferred strength of the league.  With the introduction of the Regionalliga Nordost as third tier of the league system in 1994, the "Verbandsligas" slipped to tier five.  In 2008, the league again was demoted one level when the 3. Liga was established. However, this changed nothing in the leagues status as a feeder league to the NOFV-Oberliga.  In 2020, the FLB conducted a board conference on 11 May and decided after that to terminate the 2019–20 season due to the coronavirus containment regulation issued by the Brandenburg state government during the COVID-19 pandemic in Germany, therefore there was no champion. The club at the top of the table during the termination, RSV Eintracht 1949, won promotion.  While the majority of clubs from the Brandenburg-Liga go on to play in the NOFV-Oberliga Nord, one club from the very south of the state was entered into the southern division, the NOFV-Oberliga Süd, for geographical reasons, this was the FC Energie Cottbus II.

League champions.

The league champions:

Founding members of the league.

The league was established from thirteen clubs from four leagues in 1990. Most of the East German clubs changed their names in the years after the reunion, some reverted to their old ones after a brief period, current names, when different from the one in 1990, are listed. The clubs are:  From the 2nd Division-Group A:  From the Bezirksliga Potsdam:  From the Bezirksliga Frankfurt/Oder:  From the Bezirksliga Cottbus:

The Brandenburg-Liga (VI) ("formerly the Verbandsliga Brandenburg") is the highest league for football teams exclusively in the German state of Brandenburg and at step six of the German football league system. Until the introduction of the 3. Liga in 2008 it was the fifth tier of the league system, until the introduction of the Regionalligas in 1994 the fourth tier. The champions of the Brandenburg-Liga are directly promoted to the NOFV-Oberliga Nord.

勃兰登堡联赛(,原称勃兰登堡协会联赛)是德国勃兰登堡州范围内的顶级足球赛事和德国足球联赛系统的第六级赛事。其冠军可以直接升入东北高级联赛。勃兰登堡联赛最早于1990年作为州级联赛成立;自1993-94赛季起它被称为协会联赛;自2007-08赛季起则使用现名。联赛历史积分榜的领头羊是,共参加过667场比赛。


Overview.

IBM built the computer for the U.S. Department of Energy's (DOE) National Nuclear Security Administration. It was a hybrid design with 12,960 IBM PowerXCell 8i and 6,480 AMD Opteron dual-core processors in specially designed blade servers connected by InfiniBand. The Roadrunner used Red Hat Enterprise Linux along with Fedora as its operating systems and was managed with xCAT distributed computing software. It also used the Open MPI Message Passing Interface implementation.  Roadrunner occupied approximately 296 server racks which covered and became operational in 2008. It was decommissioned March 31, 2013. The DOE used the computer for simulating how nuclear materials age in order to predict whether the USA's aging arsenal of nuclear weapons are both safe and reliable. Other uses for the Roadrunner included the science, financial, automotive and aerospace industries.

Hybrid design.

Roadrunner differed from other contemporary supercomputers because it continued the hybrid approach to supercomputer design introduced by Seymour Cray in 1964 with the Control Data Corporation CDC 6600 and continued with the order of magnitude faster CDC 7600 in 1969. However, in this architecture the peripheral processors were used only for operating system functions and all applications ran in the one central processor. Most previous supercomputers had only used one processor architecture, since it was thought to be easier to design and program for. To realize the full potential of Roadrunner, all software had to be written specially for this hybrid architecture. The hybrid design consisted of dual-core Opteron server processors manufactured by AMD using the standard AMD64 architecture. Attached to each Opteron core is an IBM-designed and -fabricated PowerXCell 8i processor. As a supercomputer, the Roadrunner was considered an Opteron cluster with Cell accelerators, as each node consists of a Cell attached to an Opteron core and the Opterons to each other.

Development.

Roadrunner was in development from 2002 and went online in 2006. Due to its novel design and complexity it was constructed in three phases and became fully operational in 2008. Its predecessor was a machine also developed at Los Alamos named Dark Horse. This machine was one of the earliest hybrid architecture systems originally based on ARM and then moved to the Cell processor. It was entirely a 3D design, its design integrated 3D memory, networking, processors and a number of other technologies.

Phase 1.

The first phase of the Roadrunner was building a standard Opteron based cluster, while evaluating the feasibility to further construct and program the future hybrid version. This Phase 1 Roadrunner reached 71 teraflops and was in full operation at Los Alamos National Laboratory in 2006.

Phase 2.

Phase 2 known as AAIS (Advanced Architecture Initial System) included building a small hybrid version of the finished system using an older version of the Cell processor. This phase was used to build prototype applications for the hybrid architecture. It went online in January 2007.

Phase 3.

The goal of Phase 3 was to reach sustained performance in excess of 1 petaflops. Additional Opteron nodes and new PowerXCell processors were added to the design. These PowerXCell processors are five times as powerful as the Cell processors used in Phase 2. It was built to full scale at IBM’s Poughkeepsie, New York facility, where it broke the 1 petaflops barrier during its fourth attempt on May 25, 2008. The complete system was moved to its permanent location in New Mexico in the summer of 2008.

Technical specifications.

Processors.

Roadrunner used two different models of processors. The first is the AMD Opteron 2210, running at 1.8 GHz. Opterons are used both in the computational nodes feeding the Cells with useful data and in the system operations and communication nodes passing data between computing nodes and helping the operators running the system. Roadrunner has a total of 6,912 Opteron processors with 6,480 used for computation and 432 for operation. The Opterons are connected together by HyperTransport links. Each Opteron has two cores for a total 13,824 cores.  The second processor is the IBM PowerXCell 8i, running at 3.2 GHz. These processors have one general purpose core (PPE), and eight special performance cores (SPE) for floating point operations. Roadrunner has a total of 12,960 PowerXCell processors, with 12,960 PPE cores and 103,680 SPE cores, for a total of 116,640 cores.

TriBlade.

Logically, a TriBlade consists of two dual-core Opterons with 16 GB RAM and four PowerXCell 8i CPUs with 16 GB Cell RAM.  Physically, a TriBlade consists of one LS21 Opteron blade, an expansion blade, and two QS22 Cell blades. The LS21 has two 1.8 GHz dual-core Opterons with 16 GB memory for the whole blade, providing 8GB for each CPU. Each QS22 has two PowerXCell 8i CPUs, running at 3.2 GHz and 8 GB memory, which makes 4 GB for each CPU. The expansion blade connects the two QS22 via four PCIe x8 links to the LS21, two links for each QS22. It also provides outside connectivity via an InfiniBand 4x DDR adapter. This makes a total width of four slots for a single TriBlade. Three TriBlades fit into one BladeCenter H chassis. The expansion blade is connected to the Opteron blade via HyperTransport.

Connected Unit (CU).

A Connected Unit is 60 BladeCenter H full of TriBlades, that is 180 TriBlades. All TriBlades are connected to a 288-port Voltaire ISR2012 Infiniband switch. Each CU also has access to the Panasas file system through twelve System x3755 servers.  CU system information:

Roadrunner cluster.

The final cluster is made up of 18 connected units, which are connected via eight additional (second-stage) Infiniband ISR2012 switches. Each CU is connected through twelve uplinks for each second-stage switch, which makes a total of 96 uplink connections.  Overall system information:

Shutdown.

IBM Roadrunner was shut down on March 31, 2013. While the supercomputer was one of the fastest in the world, its energy efficiency was relatively low. Roadrunner delivered 444 megaflops per watt vs the 886 megaflops per watt of a comparable supercomputer. Before the supercomputer is dismantled, researchers will spend one month performing memory and data routing experiments that will aid in designing future supercomputers.  After IBM Roadrunner is dismantled, the electronics will be shredded. Los Alamos will perform the majority of the supercomputer's destruction, citing the classified nature of its calculations. Some of its parts will be retained for historical purposes.

Roadrunner was a supercomputer built by IBM for the Los Alamos National Laboratory in New Mexico, USA. The US$100-million Roadrunner was designed for a peak performance of 1.7 petaflops. It achieved 1.026 petaflops on May 25, 2008, to become the world's first TOP500 LINPACK sustained 1.0 petaflops system.

走鹃(英语:Roadrunner),是一套由IBM为美国能源部(Department of Energy)所属的国家核安全管理局(NNSA)建立的超级电脑,此电脑以新墨西哥州州鸟走鹃(学名:"")命名,设于新墨西哥州的洛斯阿拉莫斯国家实验室。在2008年5月25日时,此套电脑的运算能力已达到1.026PetaFLOPS,成为前500大超级电脑中第一个持续运算能力超过<1>PetaFLOPS(10/s)者。耗资1.33亿美元。


Personal life.

John Grunsfeld was born in Chicago, Illinois to Ernest Alton 'Tony' Grunsfeld III, a distinguished Chicago architect, and Sally Mace Grunsfeld; grandson of architect Ernest Grunsfeld Jr., architect of the Adler Planetarium. He is married to the former Carol E. Schiff, with whom he has two children. Grunsfeld enjoys mountaineering, flying, sailing, bicycling, and music. His father, Ernest Grunsfeld III, died in 2011 at the age of 81.

Education.

Grunsfeld graduated from Highland Park High School in Highland Park, Illinois in 1976. He attended the Massachusetts Institute of Technology, earning a Bachelor of Science in physics in 1980. He then attended the University of Chicago, earning a Master of Science in physics in 1984 and a Doctor of Philosophy in physics in 1988.

Science career.

Grunsfeld's academic positions include that of visiting scientist, University of Tokyo/Institute of Space and Astronautical Science (1980–81); graduate research assistant, University of Chicago (1981–1985); NASA Graduate Student Fellow, University of Chicago (1985–1987); W.D. Grainger Postdoctoral Fellow in Experimental Physics, University of Chicago (1988–89); and senior research fellow, California Institute of Technology (1989–1992). Grunsfeld's research has covered x-ray and gamma-ray astronomy, high-energy cosmic ray studies, and development of new detectors and instrumentation. Grunsfeld studied binary pulsars and energetic x-ray and gamma ray sources using the NASA Compton Gamma Ray Observatory, x-ray astronomy satellites, radio telescopes, and optical telescopes including the NASA Hubble Space Telescope.

NASA career.

Grunsfeld was selected by NASA in March 1992 as an astronaut candidate and reported to the Johnson Space Center in August 1992. He completed one year of training and qualified for flight selection as a mission specialist. Grunsfeld was initially detailed to the Astronaut Office Mission Development Branch and was assigned as the lead for portable computers for use in space. Following his first flight, he led a team of engineers and computer programmers tasked with defining and producing the crew displays for command and control of the International Space Station (ISS). As part of this activity he directed an effort combining the resources of the Mission Control Center (MCC) Display Team and the Space Station Training Facility. The result was the creation of the Common Display Development Facility (CDDF), responsible for the onboard and MCC displays for the International Space Station, using object-oriented programming techniques. Following his second flight, he was assigned as Chief of the Computer Support Branch in the Astronaut Office supporting Space Shuttle and International Space Station Programs and advanced technology development. Following STS-103, he served as Chief of the Extravehicular Activity Branch in the Astronaut Office. Following STS-109, Grunsfeld served as an instructor in the Extravehicular Activity Branch, and worked on the Orbital Space Plane, exploration concepts, and technologies for use beyond low earth orbit in the Advanced Programs Branch. He served as NASA Chief Scientist assigned to NASA Headquarters from 2003 to 2004. In January 2012, he became the associate administrator for the Science Mission Directorate at NASA's headquarters in Washington, replacing Ed Weiler.  Grunsfeld has been actively engaged in communicating space science topics to the public through interviews, public lectures, and television appearances. He was recently interviewed by NASA's "Astrobiology Magazine" about the James Webb Telescope and at the Science with Hubble Space Telescope III conference in Venice, Italy, about carrying out repairs and upgrades on the Hubble Space Telescope. Recent public lectures include "Hugging Hubble" at the Space Telescope Science Institute's May 2010 Symposium, "Big Science Questions" at the 50th anniversary celebration of the Aspen Center for Physics and "The Hubble Story" presented as a special public lecture at Oxford University's Department of Physics. He has made several television appearances to discuss the successful landing of the Mars Curiosity Rover in August 2012 and its mission, including appearances on the PBS NewsHour with Judy Woodruff, the Colbert Report, and on NASAtelevision.  On April 5, 2016, Grunsfield announced his retirement from NASA, which starts from April 30.

Spaceflight experience.

STS-67/Astro-2 (March 2–18, 1995) was launched from Kennedy Space Center, Florida, and returned to land at Edwards Air Force Base, California. It was the second flight of the Astro observatory, a unique complement of three ultra-violet telescopes. During this record-setting 16-day mission, the crew conducted observations around the clock to study the far ultraviolet spectra of faint astronomical objects and the polarization of ultraviolet light coming from hot stars and distant galaxies. Mission duration was 399 hours and 9 minutes.  STS-81 (January 12–22, 1997) was a 10-day mission, the fifth to dock with Russia's Mir space station, and the second to exchange U.S. astronauts. The mission also carried the Spacehab double module providing additional middeck locker space for secondary experiments. In five days of docked operations more than three tons of food, water, experiment equipment and samples were moved back and forth between the two spacecraft. Grunsfeld served as the flight engineer on this flight. Following 160 orbits of the Earth the STS-81 mission concluded with a landing on Kennedy Space Center's Runway 33 ending a 3.9 million mile journey. Mission duration was 244 hours, 56 minutes. During this flight, Grunsfeld placed a phone call to NPR's auto-repair radio show, Car Talk. In this call he complained about his government Rockwell "van's" performance. To wit, it would run very loud and rough for about two minutes, quieter for another six and a half, and then the engine would quit. This created some consternation for the hosts until they realized that the van in question was, in fact, the Space Shuttle.  STS-103 (December 19–27, 1999) was an eight-day mission during which the crew successfully installed new gyroscopes and scientific instruments and upgraded systems on the Hubble Space Telescope (HST). Enhancing HST scientific capabilities required three space walks (EVA). Grunsfeld performed two space walks totaling 16 hours and 23 minutes. The STS-103 mission was accomplished in 120 Earth orbits, traveling 3.2 million miles in 191 hours and 11 minutes.  STS-109 (March 1–12, 2002) was the fourth Hubble Space Telescope (HST) servicing mission. The crew of STS-109 successfully upgraded the Hubble Space Telescope installing a new digital camera, a cooling system for the infrared camera, new solar arrays and a new power system. HST servicing and upgrades were accomplished by four crewmembers during a total of five EVAs in five consecutive days. Grunsfeld served as the Payload Commander on STS-109 in charge of the space walking activities and the Hubble payload. He also performed three space walks totaling 21 hours and 9 minutes, including the installation of the new Power Control Unit. STS-109 orbited the Earth 165 times, and covered 3.9 million miles in over 262 hours.  STS-125 (May 11–24, 2009) was the fifth and final servicing mission to the Hubble Space Telescope. "Atlantis" launched from Kennedy Space Center Launch Pad 39A May 11, 2009 at 2:01 p.m. EDT, and landed on May 24, 2009 at California's Edwards Air Force Base. During the mission, Grunsfeld performed three of the mission's five back-to-back spacewalks, which installed two new instruments to the Hubble Space Telescope: The Cosmic Origins Spectrograph, and the Wide Field Camera 3. The mission also replaced a Fine Guidance Sensor, six new gyroscopes, and two battery unit modules, to allow the telescope to continue to function at least through 2014. One issue Grunsfeld and his crew experienced during the overhaul was the stripping of 10mm bolts due to improper assembly and technique which he discussed again on Car Talk.  Grunsfeld has logged over 58 days in space, including eight space walks totaling 58 hours and 30 minutes.

Space Telescope Science Institute.

According to a NASA press release in January 2010, Grunsfeld indicated he would leave the agency to serve as deputy director of the Space Telescope Science Institute in Baltimore. There he helped prepare the institute for operations with NASA's planned James Webb Space Telescope. He also became a research professor in the Johns Hopkins University department of physics and astronomy in July, 2010.

Mountaineering.

Grunsfeld appeared on the PBS "NOVA" episode "Deadly Ascent", which showed him climbing Denali, the highest peak in North America, in June 2000. Grunsfeld, along with Howard Donner, (a consultant to NASA) conducted research into the effects of body temperature at high altitudes by using internal thermometers swallowed in pill form. He was able to climb to an altitude of 17,200 feet before acute altitude sickness forced him to turn back. Grunsfeld was inspired by Edmund Hillary in mountaineering.  In June 2004, Grunsfeld returned to McKinley while on vacation from NASA and successfully led a team that summitted. He is the only astronaut to have climbed to the top of Denali.

John Mace Grunsfeld (born October 10, 1958) is an American physicist and a former NASA astronaut. He is a veteran of five Space Shuttle flights and has served as NASA Chief Scientist. His academic background includes research in high energy astrophysics, cosmic ray physics and the emerging field of exoplanet studies with specific interest in future astronomical instrumentation. After retiring from NASA in 2009, he served as the Deputy Director of the Space Telescope Science Institute in Baltimore, Maryland. In January 2012, he returned to NASA and served as associate administrator of NASA's Science Mission Directorate (SMD). Grunsfeld announced his retirement from NASA in April 2016.

约翰·麦斯·格伦斯菲尔德(英语:John Mace Grunsfeld,1958年-10月10日),美国物理学家和已退役的NASA宇航员,曾任NASA首席科学家(NASA Chief Scientist)。


French era.

The name Hỏa Lò, commonly translated as "fiery furnace" or even "Hell's hole", also means "stove". The name originated from the street name phố Hỏa Lò, due to the concentration of stores selling wood stoves and coal-fire stoves along the street in pre-colonial times.  The prison was built in Hanoi by the French, in dates ranging from 1886–1889 to 1898 to 1901, when Vietnam was still part of French Indochina. The French called the prison "Maison Centrale", 'Central House', which is still the designation of prisons for dangerous or long sentence detainees in France. It was located near Hanoi's French Quarter. It was intended to hold Vietnamese prisoners, particularly political prisoners agitating for independence who were often subject to torture and execution. A 1913 renovation expanded its capacity from 460 inmates to 600. It was nevertheless often overcrowded, holding some 730 prisoners on a given day in 1916, a figure which rose to 895 in 1922 and 1,430 in 1933. By 1954 it held more than 2000 people; with its inmates held in subhuman conditions, it had become a symbol of colonialist exploitation and of the bitterness of the Vietnamese towards the French.  The central urban location of the prison also became part of its early character. During the 1910s through 1930s, street peddlers made an occupation of passing outside messages in through the jail's windows and tossing tobacco and opium over the walls; letters and packets would be thrown out to the street in the opposite direction. Within the prison itself, communication and ideas passed. Many of the future leading figures in Communist North Vietnam spent time in Maison Centrale during the 1930s and 1940s.

Democratic Republic of Vietnam, 1954.

Following the defeat at the Battle of Dien Bien Phu and the 1954 Geneva Accords the French left Hanoi and the prison came under the authority of the Democratic Republic of Vietnam. Thereafter the prison served as an education center for revolutionary doctrine and activity, and it was kept around after the French left to mark its historical significance to the North Vietnamese.

Vietnam War.

During the Vietnam War, the first U.S. prisoner to be sent to Hỏa Lò was Lieutenant Junior Grade Everett Alvarez Jr., who was shot down on August 5, 1964. From the beginning, U.S. POWs endured miserable conditions, including poor food and unsanitary conditions. The prison complex was sarcastically nicknamed the "Hanoi Hilton" by the American POWs, in reference to the well-known Hilton Hotel chain. There is some disagreement among the first group of POWs who coined the name but F8D pilot Bob Shumaker was the first to write it down, carving "Welcome to the Hanoi Hilton" on the handle of a pail to greet the arrival of Air Force Lieutenant Robert Peel.  Beginning in early 1967, a new area of the prison was opened for incoming American POWs; it was dubbed "Little Vegas", and its individual buildings and areas were named after Las Vegas Strip landmarks, such as "Golden Nugget", "Thunderbird", "Stardust", "Riviera", and the "Desert Inn". These names were chosen because many pilots had trained at Nellis Air Force Base, located in proximity to Las Vegas. American pilots were frequently already in bad shape by the time they were captured, injured either during their ejection or in landing on the ground.  The Hỏa Lò was one site used by the North Vietnamese Army to house, torture and interrogate captured servicemen, mostly American pilots shot down during bombing raids. Although North Vietnam was a signatory of the Third Geneva Convention of 1949, which demanded "decent and humane treatment" of prisoners of war, severe torture methods were employed, such as rope bindings, irons, beatings, and prolonged solitary confinement. When prisoners of war began to be released from this and other North Vietnamese prisons during the Johnson administration, their testimonies revealed widespread and systematic abuse of prisoners of war.  Regarding treatment at Hỏa Lò and other prisons, the North Vietnamese countered by stating that prisoners were treated well and in accordance with the Geneva Conventions. During 1969, they broadcast a series of coerced statements from American prisoners that purported to support this notion. The North Vietnamese also maintained that their prisons were no worse than prisons for POWs and political prisoners in South Vietnam, such as the one on Côn Sơn Island. Mistreatment of Viet Cong and North Vietnamese prisoners and South Vietnamese dissidents in South Vietnam's prisons was indeed frequent, as was North Vietnamese abuse of South Vietnamese prisoners and their own dissidents.  Beginning in late 1969, treatment of the prisoners at Hỏa Lò and other camps became less severe and generally more tolerable. Following the late 1970 attempted rescue operation at Sơn Tây prison camp, most of the POWs at the outlying camps were moved to Hỏa Lò, so that the North Vietnamese had fewer camps to protect. This created the "Camp Unity" communal living area at Hỏa Lò, which greatly reduced the isolation of the POWs and improved their morale.

Post-war accounts.

After the implementation of the 1973 Paris Peace Accords, neither the United States nor its allies ever formally charged North Vietnam with the war crimes revealed to have been committed there. In the 2000s, the Vietnamese government has had the position that claims that prisoners were tortured at Hỏa Lò and other sites during the war are fabricated, but that Vietnam wants to move past the issue as part of establishing better relations with the U.S. Tran Trong Duyet, a jailer at Hỏa Lò beginning in 1968 and its commandant for the last three years of the war, maintained in 2008 that no prisoners were tortured. However, eyewitness accounts by American servicemen present a different account of their captivity.  After the war, Risner wrote the book "Passing of the Night" detailing his seven years at Hỏa Lò. A considerable amount of literature emerged from released POWs after repatriation, depicting Hỏa Lò and the other prisons as places where such atrocities as murder, beatings, broken bones, teeth and eardrums, dislocated limbs, starvation, serving of food contaminated with human and animal feces, and medical neglect of infections and tropical disease occurred. These details are revealed in famous accounts by McCain ("Faith of My Fathers"), Denton, Alvarez, Day, Risner, Stockdale and dozens of others.  In addition, Hỏa Lò was depicted in the 1987 Hollywood movie "The Hanoi Hilton".

Hỏa Lò in the late 1970s and early 1980s.

The prison continued to be in use after the release of the American prisoners. Among the last inmates was dissident poet Nguyễn Chí Thiện, who was reimprisoned in 1979 after attempting to deliver his poems to the British Embassy, and spent the next six years in Hỏa Lò until 1985 when he was transferred to a more modern prison. He mentions the last years of the prison, partly in fictional form, in "Hỏa Lò/Hanoi Hilton Stories" (2007).

Demolition, conversion and museum.

Most of the prison was demolished in the mid-1990s and the site now contains two high-rise buildings, one of them the 25-story Somerset Grand Hanoi serviced apartment building. Other parts have been converted into a commercial complex retaining the original French colonial walls.  Only part of the prison exists today as a museum. The displays mainly show the prison during the French colonial period, including the guillotine room, still with original equipment, and the quarters for male and female Vietnamese political prisoners. Exhibits related to the American prisoners include the interrogation room where many newly captured Americans were questioned (notorious among former prisoners as the "blue room") is now made up to look like a very comfortable, if spartan, barracks-style room. Displays in the room claim that Americans were treated well and not harmed (and even cite the nickname "Hanoi Hilton" as proof that inmates found the accommodations comparable to a hotel's). Propaganda in the museum includes pictures of American POWs playing chess, shooting pool, gardening, raising chickens, and receiving large fish and eggs for food. The museum's claims are contested by former prisoners' published memoirs, and oral histories broadcast on C-SPAN identify the room (and other nearby locales) as the site of numerous acts of torture.

Hỏa Lò Prison () was a prison used by the French colonists in French Indochina for political prisoners, and later by North Vietnam for U.S. prisoners of war during the Vietnam War. During this later period it was known to American POWs as the Hanoi Hilton. The prison was demolished during the 1990s, although the gatehouse remains as a museum.

火炉监狱()是越南战争期间,北越用作关押战俘的一所监狱。


Description.

Dilophosaurids were large bipedal predators with lengths of 4 to 7 metres and estimated adult weights of 300 to 500 kg. They are well known for their distinctive head crests, which were probably used for mating displays, or to intimidate rivals.  All dilophosaurids are characterized by a hole in the premaxilla, few maxillary teeth, a slot-shaped opening at the base of the nasal process of the premaxilla, nasolacrimal crests, and a number of dorsal tab-like bumps on the articular, which is located on the back end of the lower jaw.

Body size.

"Dilophosaurus" had an average femur length of 552 mm, body lengths of 6 to 7 meters, and body masses of 362 kg. The dilophosaurid "Dracovenator" had a body length of approximately 5.5 to 7.0 meters long.  Due to a lack of endemism of Dilophosauridae, body size has been used to weakly classify taxa to Dilophosauridae. "Dilophosaurus" and "Dracovenator" are both genera of similar body length, estimated to be around 6–7 meters in length, providing some support for these two taxa as belonging to the same family.

Classification.

The family Dilophosauridae was proposed by Alan Charig and Andrew Milner in 1990 to contain only the type genus, "Dilophosaurus". Other genera, such as "Zupaysaurus" and "Dracovenator", have since been assigned to this family, though the group has never been given a phylogenetic definition and is not currently a clade. Some studies have suggested that there was a natural group of medium-sized crested theropods which included "Dilophosaurus" as well as "Dracovenator", "Cryolophosaurus", and "Sinosaurus", though it has not been formally named Dilophosauridae. While traditionally assigned to the superfamily Coelophysoidea, these analyses suggest that dilophosaurids may have been more closely related to the group Tetanurae, comprising the more advanced megalosaurs, carnosaurs and coelurosaurs.  The following cladogram outlines the relationships of "Dilophosaurus" and its close relatives as recovered by the 2007 analysis of Smith, Makovicky, Pol, Hammer, and Currie.  In 2015, "Hendrickx et al." proposed a family tree that reflects a more restricted view of the family Dilophosauridae. Although Dilophosauridae previously included "Dilophosaurus", "Dracovenator", "Sinosaurus", and "Crylophosaurus," recent research has supported a more narrowly defined Dilophosauridae family containing only "Dilophosaurus" and "Dracovenator" and excluding "Sinosaurus" and "Crylophosaurus". This change was supported by similarities between "Dracovenator, Dilophosaurus wetherilli" and "Zupaysaurus rougieri", suggesting these taxa might form their own clade sister to Dilophosauridae, although there is no definitive evidence. "Sinosaurus" and "Crylophosaurus" are also now classified as basal tetanurans. While all of the dinosaur genera once within Dilophosauridae are characterized by a distinctive cranial crest, it is thought that this distinctive trait was convergently evolved in dilophosaurids and basal tetanurans, and thus not all are necessarily derived from the same common ancestor.  The following family tree illustrates a synthesis of the relationships of the early theropod groups compiled by Hendrickx "et al." in 2015, and follows more recent research showing a more restricted Dilophosauridae.

Paleobiology.

All dilophosaurids are known for large, distinctive, head crests. These crests have been thought to have had many different uses, including being used for display, to attract mates, or intimidate rivals. It has been suggested that the crests symbolized sexual dimorphism, but this interpretation of the crests is controversial. Another distinctive cranial feature is a notch between the premaxilla and maxilla, giving dilophosaurids a crocodile-like appearance. This makes some people, for example David B. Norman, suspect that their front teeth were too weak to bring down prey, and that they were scavengers. Tracks found in Utah might show that dilophosaurids could swim, implying that they fed on fish.

Palaeoecology.

While dilophosaurids flourished during the Early Jurassic, they were mostly extinct by the end of the Early Jurassic period (201.3-174.1 Ma). Dilophosaurid fossils have been found on two continents: "Dilophosaurus wetherilli" was discovered in North America and "Dracovenator regenti" was discovered in South Africa. The taxa previously considered Dilophosaurids, "Sinosaurus" and "Cryolophosaurus", have been found in China (Dong 2003; Xing et al. 2013a, 2014) and Antarctica, respectively.  A lack of endemism within the Dilophosauridae family makes it difficult to pinpoint a single geographic origin for the group. "Dilophosaurus" fossils originate from the Kayenta Formation (dates to Early Jurassic, 196–183 million years ago) of the southwest region of the United States. In addition to "Dilophosaurus", ‘"Syntarsus’ kayentakatae" is another taxa from the Kayenta Formation, despite being distantly related to "Dilophosaurus". "Syntarsus" similarly occurred in the Upper Elliot Formation of South Africa, where both "Dracovenator" and "Coelophysis rhodesiensis" have been found in a similar region despite not being closely related to one another.  During the Early Jurassic, many unrelated basal theropods existed in similar geographic regions, as exemplified through the Kayenta Formation and the Upper Elliot Formation. A hypothesis proposed by Smith "et al." (2007) was that there may have been resource partitioning within different geographic regions of the Early Jurassic based on differences in body size. This hypothesis, with more evidence, would help explain the lack of endemism observed in the fossil record of the Early Jurassic basal theropods.

Dilophosauridae is a family of medium to large sized theropod dinosaurs. The name Dilophosauridae is derived from Greek, with “di-” meaning “two,” “lophos” meaning “crest,” “sauros” meaning “lizard,” and “-idae” meaning “family”. While the name suggests that all dilophosaurids have two crests, this is not applicable to all dilophosaurids. The Dilophosauridae is anchored by its type genus, "Dilophosaurus", and therefore the name comes from the distinctive two crests of the genus.

双冠龙科(学名:Dilophosaurus)、旧译双脊龙科、双棘龙科,为一群侏罗纪早期的中型以及大型肉食性恐龙的总称。


Formalization.

A corner can be defined as the intersection of two edges. A corner can also be defined as a point for which there are two dominant and different edge directions in a local neighbourhood of the point.  An interest point is a point in an image which has a well-defined position and can be robustly detected. This means that an interest point can be a corner but it can also be, for example, an isolated point of local intensity maximum or minimum, line endings, or a point on a curve where the curvature is locally maximal.  In practice, most so-called corner detection methods detect interest points in general, and in fact, the term "corner" and "interest point" are used more or less interchangeably through the literature. As a consequence, if only corners are to be detected it is necessary to do a local analysis of detected interest points to determine which of these are real corners. Examples of edge detection that can be used with post-processing to detect corners are the Kirsch operator and the Frei-Chen masking set.  "Corner", "interest point" and "feature" are used interchangeably in literature, confusing the issue. Specifically, there are several blob detectors that can be referred to as "interest point operators", but which are sometimes erroneously referred to as "corner detectors". Moreover, there exists a notion of ridge detection to capture the presence of elongated objects.  Corner detectors are not usually very robust and often require large redundancies introduced to prevent the effect of individual errors from dominating the recognition task.  One determination of the quality of a corner detector is its ability to detect the same corner in multiple similar images, under conditions of different lighting, translation, rotation and other transforms.  A simple approach to corner detection in images is using correlation, but this gets very computationally expensive and suboptimal. An alternative approach used frequently is based on a method proposed by Harris and Stephens (below), which in turn is an improvement of a method by Moravec.

Moravec corner detection algorithm.

This is one of the earliest corner detection algorithms and defines a "corner" to be a point with low self-similarity. The algorithm tests each pixel in the image to see if a corner is present, by considering how similar a patch centered on the pixel is to nearby, largely overlapping patches. The similarity is measured by taking the sum of squared differences (SSD) between the corresponding pixels of two patches. A lower number indicates more similarity.  If the pixel is in a region of uniform intensity, then the nearby patches will look similar. If the pixel is on an edge, then nearby patches in a direction perpendicular to the edge will look quite different, but nearby patches in a direction parallel to the edge will result in only a small change. If the pixel is on a feature with variation in all directions, then none of the nearby patches will look similar.  The corner strength is defined as the smallest SSD between the patch and its neighbours (horizontal, vertical and on the two diagonals). The reason is that if this number is high, then the variation along all shifts is either equal to it or larger than it, so capturing that all nearby patches look different.  If the corner strength number is computed for all locations, that it is locally maximal for one location indicates that a feature of interest is present in it.  As pointed out by Moravec, one of the main problems with this operator is that it is not isotropic: if an edge is present that is not in the direction of the neighbours (horizontal, vertical, or diagonal), then the smallest SSD will be large and the edge will be incorrectly chosen as an interest point.

The Harris & Stephens / Shi–Tomasi corner detection algorithms.

See Harris Corner Detector.  Harris and Stephens improved upon Moravec's corner detector by considering the differential of the corner score with respect to direction directly, instead of using shifted patches. (This corner score is often referred to as autocorrelation, since the term is used in the paper in which this detector is described. However, the mathematics in the paper clearly indicate that the sum of squared differences is used.)  Without loss of generality, we will assume a grayscale 2-dimensional image is used. Let this image be given by formula_1. Consider taking an image patch over the area formula_2 and shifting it by formula_3. The weighted "sum of squared differences" (SSD) between these two patches, denoted formula_4, is given by:  formula_6 can be approximated by a Taylor expansion. Let formula_7 and formula_8 be the partial derivatives of formula_9, such that  This produces the approximation  which can be written in matrix form:  where "A" is the structure tensor,  Angle brackets denote averaging (i.e. summation over formula_14). formula_15 denotes the type of window that slides over the image. If a Box filter is used the response will be anisotropic, but if a Gaussian is used, then the response will be isotropic.  A corner (or in general an interest point) is characterized by a large variation of formula_16 in all directions of the vector formula_17. By analyzing the eigenvalues of formula_18, this characterization can be expressed in the following way: formula_18 should have two "large" eigenvalues for an interest point. Based on the magnitudes of the eigenvalues, the following inferences can be made based on this argument:  Harris and Stephens note that exact computation of the eigenvalues is computationally expensive, since it requires the computation of a square root, and instead suggest the following function formula_27, where formula_28 is a tunable sensitivity parameter:  Therefore, the algorithm does not have to actually compute the eigenvalue decomposition of the matrix formula_30 and instead it is sufficient to evaluate the determinant and trace of formula_30 to find corners, or rather interest points in general.  The Shi–Tomasi corner detector directly computes formula_32 because under certain assumptions, the corners are more stable for tracking. Note that this method is also sometimes referred to as the Kanade–Tomasi corner detector.  The value of formula_28 has to be determined empirically, and in the literature values in the range 0.04–0.15 have been reported as feasible.  One can avoid setting the parameter formula_28 by using Noble's corner measure formula_35 which amounts to the harmonic mean of the eigenvalues: formula_37 being a small positive constant.  "If" formula_30 can be interpreted as the precision matrix for the corner position, the covariance matrix for the corner position is formula_39, i.e.  The sum of the eigenvalues of formula_39, which in that case can be interpreted as a generalized variance (or a "total uncertainty") of the corner position, is related to Noble's corner measure formula_35 by the following equation:

The Förstner corner detector.

In some cases, one may wish to compute the location of a corner with subpixel accuracy. To achieve an approximate solution, the Förstner algorithm solves for the point closest to all the tangent lines of the corner in a given window and is a least-square solution. The algorithm relies on the fact that for an ideal corner, tangent lines cross at a single point.  The equation of a tangent line formula_44 at pixel formula_45 is given by:  where formula_47 is the gradient vector of the image formula_1 at formula_45.  The point formula_50 closest to all the tangent lines in the window formula_51 is:  The distance from formula_50 to the tangent lines formula_54 is weighted by the gradient magnitude, thus giving more importance to tangents passing through pixels with strong gradients.  Solving for formula_50:  formula_57 are defined as:  Minimizing this equation can be done by differentiating with respect to formula_59 and setting it equal to 0:  Note that formula_61 is the structure tensor. For the equation to have a solution, formula_30 must be invertible, which implies that formula_30 must be full rank (rank 2). Thus, the solution  only exists where an actual corner exists in the window formula_51.  A methodology for performing "automatic scale selection" for this corner localization method has been presented by Lindeberg by minimizing the normalized residual  over scales. Thereby, the method has the ability to automatically adapt the scale levels for computing the image gradients to the noise level in the image data, by choosing coarser scale levels for noisy image data and finer scale levels for near ideal corner-like structures.  Notes:

The multi-scale Harris operator.

The computation of the second moment matrix (sometimes also referred to as the structure tensor) formula_30 in the Harris operator, requires the computation of image derivatives formula_70 in the image domain as well as the summation of non-linear combinations of these derivatives over local neighbourhoods. Since the computation of derivatives usually involves a stage of scale-space smoothing, an operational definition of the Harris operator requires two scale parameters: (i) a "local scale" for smoothing prior to the computation of image derivatives, and (ii) an "integration scale" for accumulating the non-linear operations on derivative operators into an integrated image descriptor.  With formula_1 denoting the original image intensity, let formula_72 denote the scale space representation of formula_1 obtained by convolution with a Gaussian kernel with local scale parameter formula_75: and let formula_77 and formula_78 denote the partial derivatives of formula_72. Moreover, introduce a Gaussian window function formula_80 with integration scale parameter formula_81. Then, the "multi-scale second-moment matrix" can be defined as Then, we can compute eigenvalues of formula_83 in a similar way as the eigenvalues of formula_30 and define the "multi-scale Harris corner measure" as Concerning the choice of the local scale parameter formula_75 and the integration scale parameter formula_81, these scale parameters are usually coupled by a relative integration scale parameter formula_88 such that formula_89, where formula_88 is usually chosen in the interval formula_91. Thus, we can compute the multi-scale Harris corner measure formula_92 at any scale formula_75 in scale-space to obtain a multi-scale corner detector, which responds to corner structures of varying sizes in the image domain.  In practice, this multi-scale corner detector is often complemented by a "scale selection step", where the scale-normalized Laplacian operator is computed at every scale in scale-space and "scale adapted corner points with automatic scale selection" (the "Harris-Laplace operator") are computed from the points that are simultaneously:

The level curve curvature approach.

An earlier approach to corner detection is to detect points where the curvature of level curves and the gradient magnitude are "simultaneously" high. A differential way to detect such points is by computing "the rescaled level curve curvature" (the product of the level curve curvature and the gradient magnitude raised to the power of three) and to detect positive maxima and negative minima of this differential expression at some scale formula_75 in the scale space representation formula_72 of the original image. A main problem when computing the rescaled level curve curvature entity at a single scale however, is that it may be sensitive to noise and to the choice of the scale level. A better method is to compute the "formula_88-normalized rescaled level curve curvature" with formula_104 and to detect "signed scale-space extrema" of this expression, that are points and scales that are positive maxima and negative minima with respect to both space and scale in combination with a complementary localization step to handle the increase in localization error at coarser scales. In this way, larger scale values will be associated with rounded corners of large spatial extent while smaller scale values will be associated with sharp corners with small spatial extent. This approach is the first corner detector with automatic scale selection (prior to the "Harris-Laplace operator" above) and has been used for tracking corners under large scale variations in the image domain and for matching corner responses to edges to compute structural image features for geon-based object recognition.

Laplacian of Gaussian, differences of Gaussians and determinant of the Hessian scale-space interest points.

LoG is an acronym standing for "Laplacian of Gaussian", DoG is an acronym standing for "difference of Gaussians" (DoG is an approximation of LoG), and DoH is an acronym standing for "determinant of the Hessian." These scale-invariant interest points are all extracted by detecting scale-space extrema of scale-normalized differential expressions, i.e., points in scale-space where the corresponding scale-normalized differential expressions assume local extrema with respect to both space and scale where formula_107 denotes the appropriate scale-normalized differential entity (defined below).  These detectors are more completely described in blob detection. The scale-normalized Laplacian of the Gaussian and difference-of-Gaussian features (Lindeberg 1994, 1998; Lowe 2004) do not necessarily make highly selective features, since these operators may also lead to responses near edges. To improve the corner detection ability of the differences of Gaussians detector, the feature detector used in the SIFT system therefore uses an additional post-processing stage, where the eigenvalues of the Hessian of the image at the detection scale are examined in a similar way as in the Harris operator. If the ratio of the eigenvalues is too high, then the local image is regarded as too edge-like, so the feature is rejected. Also Lindeberg's Laplacian of the Gaussian feature detector can be defined to comprise complementary thresholding on a complementary differential invariant to suppress responses near edges.  The scale-normalized determinant of the Hessian operator (Lindeberg 1994, 1998) is on the other hand highly selective to well localized image features and does only respond when there are significant grey-level variations in two image directions and is in this and other respects a better interest point detector than the Laplacian of the Gaussian. The determinant of the Hessian is an affine covariant differential expression and has better scale selection properties under affine image transformations than the Laplacian operator (Lindeberg 2013, 2015). Experimentally this implies that determinant of the Hessian interest points have better repeatability properties under local image deformation than Laplacian interest points, which in turns leads to better performance of image-based matching in terms higher efficiency scores and lower 1-precision scores.  The scale selection properties, affine transformation properties and experimental properties of these and other scale-space interest point detectors are analyzed in detail in (Lindeberg 2013, 2015).

Scale-space interest points based on the Lindeberg Hessian feature strength measures.

Inspired by the structurally similar properties of the Hessian matrix formula_110 of a function formula_111 and the second-moment matrix (structure tensor) formula_83, as can e.g. be manifested in terms of their similar transformation properties under affine image deformations Lindeberg (2013, 2015) proposed to define four feature strength measures from the Hessian matrix in related ways as the Harris and Shi-and-Tomasi operators are defined from the structure tensor (second-moment matrix). Specifically, he defined the following unsigned and signed Hessian feature strength measures: where formula_119 and formula_120 denote the trace and the determinant of the Hessian matrix formula_121 of the scale-space representation formula_72 at any scale formula_75, whereas denote the eigenvalues of the Hessian matrix.  The unsigned Hessian feature strength measure formula_126 responds to local extrema by positive values and is not sensitive to saddle points, whereas the signed Hessian feature strength measure formula_127 does additionally respond to saddle points by negative values. The unsigned Hessian feature strength measure formula_128 is insensitive to the local polarity of the signal, whereas the signed Hessian feature strength measure formula_129 responds to the local polarity of the signal by the sign of its output.  In Lindeberg (2015) these four differential entities were combined with local scale selection based on either scale-space extrema detection or scale linking. Furthermore, the signed and unsigned Hessian feature strength measures formula_128 and formula_129 were combined with complementary thresholding on formula_133.  By experiments on image matching under scaling transformations on a poster dataset with 12 posters with multi-view matching over scaling transformations up to a scaling factor of 6 and viewing direction variations up to a slant angle of 45 degrees with local image descriptors defined from reformulations of the pure image descriptors in the SIFT and SURF operators to image measurements in terms of Gaussian derivative operators (Gauss-SIFT and Gauss-SURF) instead of original SIFT as defined from an image pyramid or original SURF as defined from Haar wavelets, it was shown that scale-space interest point detection based on the unsigned Hessian feature strength measure formula_126 allowed for the best performance and better performance than scale-space interest points obtained from the determinant of the Hessian formula_135. Both the unsigned Hessian feature strength measure formula_126, the signed Hessian feature strength measure formula_127 and the determinant of the Hessian formula_138 allowed for better performance than the Laplacian of the Gaussian formula_139. When combined with scale linking and complementary thresholding on formula_133, the signed Hessian feature strength measure formula_129 did additionally allow for better performance than the Laplacian of the Gaussian formula_142.  Furthermore, it was shown that all these differential scale-space interest point detectors defined from the Hessian matrix allow for the detection of a larger number of interest points and better matching performance compared to the Harris and Shi-and-Tomasi operators defined from the structure tensor (second-moment matrix).  A theoretical analysis of the scale selection properties of these four Hessian feature strength measures and other differential entities for detecting scale-space interest points, including the Laplacian of the Gaussian and the determinant of the Hessian, is given in Lindeberg (2013) and an analysis of their affine transformation properties as well as experimental properties in Lindeberg (2015).

Affine-adapted interest point operators.

The interest points obtained from the multi-scale Harris operator with automatic scale selection are invariant to translations, rotations and uniform rescalings in the spatial domain. The images that constitute the input to a computer vision system are, however, also subject to perspective distortions. To obtain an interest point operator that is more robust to perspective transformations, a natural approach is to devise a feature detector that is "invariant to affine transformations". In practice, affine invariant interest points can be obtained by applying affine shape adaptation where the shape of the smoothing kernel is iteratively warped to match the local image structure around the interest point or equivalently a local image patch is iteratively warped while the shape of the smoothing kernel remains rotationally symmetric (Lindeberg 1993, 2008; Lindeberg and Garding 1997; Mikolajzcyk and Schmid 2004). Hence, besides the commonly used multi-scale Harris operator, affine shape adaptation can be applied to other corner detectors as listed in this article as well as to differential blob detectors such as the Laplacian/difference of Gaussian operator, the determinant of the Hessian and the Hessian–Laplace operator.

The Wang and Brady corner detection algorithm.

The Wang and Brady detector considers the image to be a surface, and looks for places where there is large curvature along an image edge. In other words, the algorithm looks for places where the edge changes direction rapidly. The corner score, formula_143, is given by:  where formula_145 is the unit vector perpendicular to the gradient, and formula_67 determines how edge-phobic the detector is. The authors also note that smoothing (Gaussian is suggested) is required to reduce noise.  Smoothing also causes displacement of corners, so the authors derive an expression for the displacement of a 90 degree corner, and apply this as a correction factor to the detected corners.

The SUSAN corner detector.

SUSAN is an acronym standing for "smallest univalue segment assimilating nucleus." This method is the subject of a 1994 UK patent which is no longer in force.  For feature detection, SUSAN places a circular mask over the pixel to be tested (the nucleus). The region of the mask is formula_147, and a pixel in this mask is represented by formula_148. The nucleus is at formula_149. Every pixel is compared to the nucleus using the comparison function:  where formula_75 is the brightness difference threshold, formula_1 is the brightness of the pixel and the power of the exponent has been determined empirically. This function has the appearance of a smoothed top-hat or rectangular function. The area of the SUSAN is given by:  If formula_67 is the rectangular function, then formula_155 is the number of pixels in the mask which are within formula_75 of the nucleus. The response of the SUSAN operator is given by:  where formula_158 is named the `geometric threshold'. In other words, the SUSAN operator only has a positive score if the area is small enough. The smallest SUSAN locally can be found using non-maximal suppression, and this is the complete SUSAN operator.  The value formula_75 determines how similar points have to be to the nucleus before they are considered to be part of the univalue segment. The value of formula_158 determines the minimum size of the univalue segment. If formula_158 is large enough, then this becomes an edge detector.  For corner detection, two further steps are used. Firstly, the centroid of the SUSAN is found. A proper corner will have the centroid far from the nucleus. The second step insists that all points on the line from the nucleus through the centroid out to the edge of the mask are in the SUSAN.

The Trajkovic and Hedley corner detector.

In a manner similar to SUSAN, this detector directly tests whether a patch under a pixel is self-similar by examining nearby pixels. formula_162 is the pixel to be considered, and formula_163 is point on a circle formula_164 centered around formula_162. The point formula_166 is the point opposite to formula_167 along the diameter.  The response function is defined as:  This will be large when there is no direction in which the centre pixel is similar to two nearby pixels along a diameter. formula_164 is a discretised circle (a Bresenham circle), so interpolation is used for intermediate diameters to give a more isotropic response. Since any computation gives an upper bound on the formula_170, the horizontal and vertical directions are checked first to see if it is worth proceeding with the complete computation of formula_67.

AST-based feature detectors.

AST is an acronym standing for "accelerated segment test." This test is a relaxed version of the SUSAN corner criterion. Instead of evaluating the circular disc, only the pixels in a Bresenham circle of radius formula_172 around the candidate point are considered. If formula_155 contiguous pixels are all brighter than the nucleus by at least formula_75 or all darker than the nucleus by formula_75, then the pixel under the nucleus is considered to be a feature. This test is reported to produce very stable features. The choice of the order in which the pixels are tested is a so-called Twenty Questions problem. Building short decision trees for this problem results in the most computationally efficient feature detectors available.  The first corner detection algorithm based on the AST is FAST (features from accelerated segment test). Although formula_172 can in principle take any value, FAST uses only a value of 3 (corresponding to a circle of 16 pixels circumference), and tests show that the best results are achieved with formula_155 being 9. This value of formula_155 is the lowest one at which edges are not detected. The order in which pixels are tested is determined by the ID3 algorithm from a training set of images. Confusingly, the name of the detector is somewhat similar to the name of the paper describing Trajkovic and Hedley's detector.

Automatic synthesis of detectors.

Trujillo and Olague introduced a method by which genetic programming is used to automatically synthesize image operators that can detect interest points. The terminal and function sets contain primitive operations that are common in many previously proposed man-made designs. Fitness measures the stability of each operator through the repeatability rate, and promotes a uniform dispersion of detected points across the image plane. The performance of the evolved operators has been confirmed experimentally using training and testing sequences of progressively transformed images. Hence, the proposed GP algorithm is considered to be human-competitive for the problem of interest point detection.

Spatio-temporal interest point detectors.

The Harris operator has been extended to space-time by Laptev and Lindeberg. Let formula_83 denote the spatio-temporal second-moment matrix defined by  Then, for a suitable choice of formula_181, spatio-temporal interest points are detected from spatio-temporal extrema of the following spatio-temporal Harris measure:  The determinant of the Hessian operator has been extended to joint space-time by Willems et al and Lindeberg, leading to the following scale-normalized differential expression:  In the work by Willems et al, a simpler expression corresponding to formula_184 and formula_185 was used. In Lindeberg, it was shown that formula_186 and formula_187 implies better scale selection properties in the sense that the selected scale levels obtained from a spatio-temporal Gaussian blob with spatial extent formula_188 and temporal extent formula_189 will perfectly match the spatial extent and the temporal duration of the blob, with scale selection performed by detecting spatio-temporal scale-space extrema of the differential expression.  The Laplacian operator has been extended to spatio-temporal video data by Lindeberg, leading to the following two spatio-temporal operators, which also constitute models of receptive fields of non-lagged vs. lagged neurons in the LGN:  For the first operator, scale selection properties call for using formula_184 and formula_193, if we want this operator to assume its maximum value over spatio-temporal scales at a spatio-temporal scale level reflecting the spatial extent and the temporal duration of an onset Gaussian blob. For the second operator, scale selection properties call for using formula_184 and formula_195, if we want this operator to assume its maximum value over spatio-temporal scales at a spatio-temporal scale level reflecting the spatial extent and the temporal duration of a blinking Gaussian blob.  Colour extensions of spatio-temporal interest point detectors have been investigated by Everts et al.

Corner detection is an approach used within computer vision systems to extract certain kinds of features and infer the contents of an image. Corner detection is frequently used in motion detection, image registration, video tracking, image mosaicing, panorama stitching, 3D reconstruction and object recognition. Corner detection overlaps with the topic of interest point detection.

角检测(英语:Corner detection)或兴趣点检测(英语:interest point detection),是计算机视觉系统中用来提取特征以及推测图像内容的一种方法.角检测的应用很广,经常用在运动检测,跟踪,图像镶嵌(image mosaicing),全景图缝合(panorama stiching),三维建模以及物体识别中.