A* is a graph traversal and path search algorithm, used in computer science due to its completeness and optimal efficiency. One major practical drawback is its O space complexity. Thus, in practical travel-routing systems, it is outperformed by algorithms which can pre-process the graph to attain better performance, as well as memory-bounded approaches. Peter Hart, Nils Nilsson and Bertram Raphael of Stanford Research Institute first published the algorithm in 1968, it can be seen as an extension of Edsger Dijkstra's 1959 algorithm. A* achieves better performance by using heuristics to guide its search. A* was created as part of the Shakey project, which had the aim of building a mobile robot that could plan its own actions. Nils Nilsson proposed using the Graph Traverser algorithm for Shakey's path planning. Graph Traverser is guided by a heuristic function h, the estimated distance from node n to the goal node: it ignores g, the distance from the start node to n. Bertram Raphael suggested using the sum, g + h. Peter Hart invented the concepts we now call admissibility and consistency of heuristic functions.
A* was designed for finding least-cost paths when the cost of a path is the sum of its edge costs, but it has been shown that A* can be used to find optimal paths for any problem satisfying the conditions of a cost algebra. The original 1968 A* paper contained a theorem that no A*-like algorithm could expand fewer nodes than A* if the heuristic function is consistent and A*’s tie-breaking rule is suitably chosen. A ″correction″ was published a few years claiming that consistency was not required, but this was shown to be false in Dechter and Pearl’s definitive study of A*'s optimality, which gave an example of A* with a heuristic, admissible but not consistent expanding arbitrarily more nodes than an alternative A*-like algorithm. A* is an informed search algorithm, or a best-first search, meaning that it is formulated in terms of weighted graphs: starting from a specific starting node of a graph, it aims to find a path to the given goal node having the smallest cost, it does this by maintaining a tree of paths originating at the start node and extending those paths one edge at a time until its termination criterion is satisfied.
At each iteration of its main loop, A * needs to determine. It does so based on the cost of the path and an estimate of the cost required to extend the path all the way to the goal. A* selects the path that minimizes f = g + h where n is the next node on the path, g is the cost of the path from the start node to n, h is a heuristic function that estimates the cost of the cheapest path from n to the goal. A* terminates when the path it chooses to extend is a path from start to goal or if there are no paths eligible to be extended; the heuristic function is problem-specific. If the heuristic function is admissible, meaning that it never overestimates the actual cost to get to the goal, A* is guaranteed to return a least-cost path from start to goal. Typical implementations of A* use a priority queue to perform the repeated selection of minimum cost nodes to expand; this priority queue is known as fringe. At each step of the algorithm, the node with the lowest f value is removed from the queue, the f and g values of its neighbors are updated accordingly, these neighbors are added to the queue.
The algorithm continues. The f value of the goal is the cost of the shortest path, since h at the goal is zero in an admissible heuristic; the algorithm described so far gives us only the length of the shortest path. To find the actual sequence of steps, the algorithm can be revised so that each node on the path keeps track of its predecessor. After this algorithm is run, the ending node will point to its predecessor, so on, until some node's predecessor is the start node; as an example, when searching for the shortest route on a map, h might represent the straight-line distance to the goal, since, physically the smallest possible distance between any two points. If the heuristic h satisfies the additional condition h ≤ d + h for every edge of the graph h is called monotone, or consistent. With a consistent heuristic, A* is guaranteed to find an optimal path without processing any node more than once and A* is equivalent to running Dijkstra's algorithm with the reduced cost d' = d + h − h; the following pseudocode describes the algorithm: Remark: In this pseudocode, if a node is reached by one path, removed from openSet, subsequently reached by a cheaper path, it will be added to openSet again.
This is essential to guarantee that the path returned is optimal if the heuristic function is admissible but not consistent. If the heuristic is consistent, when a node is removed from open
The Borough of Port Fairy was a local government area about 290 kilometres west-southwest of Melbourne, the state capital of Victoria, Australia. The borough covered an area of 22.72 square kilometres, existed from 1856 until 1994. Its area was surrounded by the Shire of the Southern Ocean. Port Fairy was incorporated as the Belfast Municipal District on 1 July 1856, becoming a borough on 1 October 1863. On 27 May 1887 it was renamed Port Fairy. On 23 September 1994, the Borough was abolished, merged with Tower Hill Reserve, the Shires of Belfast and Minhamite, most of Warrnambool and Mortlake and parts of Dundas and Mount Rouse into the Shire of Moyne; the Borough of Port Fairy was not subdivided into wards, the seven councillors represented the entire area. * Estimate in the 1958 Victorian Year Book
Unterems is a former municipality in the district of Leuk in the canton of Valais in Switzerland. The municipalities of Turtmann and Unterems merged on 1 January 2013 into the new municipality of Turtmann-Unterems. Unterems is first mentioned in 1270 as inferiorem hemesa. Unterems had an area, as of 2011, of 1.4 square kilometers. Of this area, 39.1 % is used for agricultural purposes. Of the rest of the land, 7.2% is settled and 0.0% is unproductive land. The former municipality is located in the Leuk district, high on the left side of the Rhone valley, it consists of the village of Unterems and the hamlets of Ze Schmidu and Prupräsu. The blazon of the municipal coat of arms is Azure a Cross Patee Gules in chief two Mullets of Six Or in base a branch of Lime Tree/Linden Tree slipped with three Leaves Vert. Unterems had a population of 142; as of 2008, 2.5% of the population are resident foreign nationals. Over the last 10 years the population has changed at a rate of 5.9%. It has changed at a rate of -15.7 % due to births and deaths.
Most of the population speaks German as their first language, French and Spanish are all spoken by 1 person. As of 2008, the gender distribution of the population was 56.8 % female. The population was made up of non-Swiss men. There were 4 non-Swiss women. Of the population in the municipality 89 or about 55.3% were born in Unterems and lived there in 2000. There were 46 or 28.6% who were born in the same canton, while 13 or 8.1% were born somewhere else in Switzerland, 3 or 1.9% were born outside of Switzerland. The age distribution of the population is children and teenagers make up 19.3% of the population, while adults make up 55.3% and seniors make up 25.5%. As of 2000, there were 59 people who never married in the municipality. There were 2 individuals who are divorced; as of 2000, there were 56 private households in the municipality, an average of 2.5 persons per household. There were 17 households that consist of 4 households with five or more people. Out of a total of 59 households that answered this question, 28.8% were households made up of just one person and there were 2 adults who lived with their parents.
Of the rest of the households, there are 13 married couples without children, 23 married couples with children There was 1 household, made up of unrelated people and 3 households that were made up of some sort of institution or another collective housing. In 2000 there were 71 single family homes out of a total of 98 inhabited buildings. There were 17 multi-family buildings, along with 8 multi-purpose buildings that were used for housing and 2 other use buildings that had some housing. In 2000, a total of 51 apartments were permanently occupied, while 66 apartments were seasonally occupied and 7 apartments were empty; the historical population is given in the following chart: In the 2007 federal election the most popular party was the CVP which received 48.11% of the vote. The next three most popular parties were the SP and the Green Party. In the federal election, a total of 82 votes were cast, the voter turnout was 66.1%. In the 2009 Conseil d'Etat/Staatsrat election a total of 66 votes were cast, of which or about 0.0% were invalid.
The voter participation was 54.6%, similar to the cantonal average of 54.67%. In the 2007 Swiss Council of States election a total of 81 votes were cast, of which 1 or about 1.2% were invalid. The voter participation was 65.3%, much more than the cantonal average of 59.88%. As of 2010, Unterems had an unemployment rate of 0.7%. As of 2008, there were 19 people employed in the primary economic sector and about 8 businesses involved in this sector. No one was employed in the secondary sector. 79 people were employed with 5 businesses in this sector. There were 64 residents of the municipality who were employed in some capacity, of which females made up 45.3% of the workforce. In 2008 the total number of full-time equivalent jobs was 53; the number of jobs in the primary sector was 9. There were no jobs in the secondary sector; the number of jobs in the tertiary sector was 44. In the tertiary sector. In 2000, there were 7 workers who commuted into 43 workers who commuted away; the municipality is a net exporter of workers, with about 6.1 workers leaving the municipality for every one entering.
Of the working population, 17.2% used public transportation to get to work, 53.1% used a private car. From the 2000 census, 146 or 90.7% were Roman Catholic, while 6 or 3.7% belonged to the Swiss Reformed Church. In Unterems about 48 or of the population have completed non-mandatory upper secondary education, 7 or have completed additional higher education. Of the 7 who completed tertiary schooling, 57.1% were Swiss men, 42.9% were Swiss women. As of 2000, there were 8 students in Unterems who came from another municipality, while 15 residents attended schools outside the municipality. Official website Media related to Unterems at Wikimedia Commons
Triumph Hotels is a collection of historic boutique hotels located in New York City which includes the Hotel Belleclaire, The Iroquois Hotel and the Hotel Edison, among others. The hotels have hosted a range of famous guests throughout history, including James Dean, Abraham Lincoln and Mark Twain; the hotel brand is co-owned by Shimmie Horn. James Dean lived in the Iroquois, which served as the headquarters of The National Council of the Arts and Professionals in 1949; the seminal British punk band the Clash wrote the song Rock the Casbah while staying at the Iroquois. Hotel Edison's namesake Thomas Edison turned on the lights at the hotel's grand opening and both the building and its restaurants have since been featured in several films, including The Godfather, Bullets Over Broadway and Birdman. In November, 2017 the Hotel Chandler was shut down and converted into the area's first homeless shelter for New York City families; the Iroquois New York The Frederick Hotel The Evelyn The Hotel Belleclaire The Washington Jefferson The Hotel Edison
Dibulla is a town and municipality located in the Department of La Guajira, Colombia by the Caribbean sea and the Sierra Nevada de Santa Marta mountains on the Guajira Peninsula. It was proclaimed municipality in 1995; the town is recognized for being the birthplace of renown vallenato composer Carlos Huertas and his song "El Cantor de Fonseca". Dibulla limits to the west with the Magdalena Department. Located 74 km away from La Guajira's capital Riohacha en route to the city of Santa Marta, it is crossed by the river of the same name, the Dibulla River and the Jérez River; the municipality has its only 2 m above sea level. The average temperature is of 28 °C, its main attraction relies on a recreational center called Maziruma, a beach resort. The area of present-day municipality of Dibuya was inhabited predominantly during the Pre-Columbian era by indigenous tribes pertaining to the Koguis and Guanebucanes ethnic groups descendants of the Tairona civilization with a direct influence from the Wayuu ethnic group.
During the Spanish colonization of the Americas, the indigenous village of Yaharo was first seen by Spanish explorers upon reaching the coasts of the Guajira Peninsula in 1502. In 1525, Spanish explorer Rodrigo de Bastidas visited the Yaharo Town and registered an account of the village. A year before, in 1524 Bastidas had created the Government of Santa Marta which covered an area from Cabo de la Vela to the mouth of the Magdalena River. Between 1609 and 1640, the Spanish colonizers imported some 800 or more African slaves. Most of these escaped and formed Palenques. In 1679 the Government of Santa Marta offered these palenques their freedom in exchange of protecting the territory from English pirates. In 1846 President of Colombia, Gen. Tomas Cipriano de Mosquera ordered the reestablishment of the government after the War of the Supremes civil war. Yaharo was renamed to Dibuya which translates from the Guanebucan language to "lagoon by the sea", lagoon, located in the region of the Ramada. In 1872 Dibuya became a municipality seat or district by law 216 of this same year and was part of the Department of Magdalena.
In 1886 this category was removed by interim governor of the department Luis Cotes by Decree 377 of February 17, 1886 when the United States of Colombia was dissolved. The Council of Riohacha formally created the Corregimiento of Dibuya on April 1, 1887. From the 1970s and until 1989 two families from the Department of La Guajira; the confrontation between the two families gained national attention and directly affected those family members living in Dibuya, as well as those living from Barranquilla and Santa Marta to Riohacha and Valledupar in the Caribbean Region of Colombia. On December 5, 1995 the Department Assembly of La Guajira created the Municipalilty of Dibuya by Ordinance 030 of that same year. Cristian Montero Córdoba became its first appointed mayor by Decree 350 of December 28, 1995; the Municipality of Dibulla is made formed by five corregimientos, two inspecciones de policía and twenty nine veredas: El Peru La Marina Las casitas Miramar Rincon Guapo Tierra Baja Campana Nuevo La Punta de los Remedios Las Flores Mingueo Palomino Rio Ancho Casa Aluminio Chimgale Cuatro Veredas El Cerro Jerez El Limonal Larga La Vida Mosca Gobernacion de La Guajira - Dibulla Dibulla official website
The Basement Wall was an American garage rock band from Baton Rouge, who were active in the 1960s. The group spent much of their career touring in Texas, became among the most recognized live acts in the southern regional rock scene. All of the band's recorded material was featured on a compilation album in 1985. In 2005, they reunited with their original members for a concert to mark the occasion of their induction into the Louisiana Entertainment Hall of Fame; the Basement Wall formed in 1963 by founding members Terry Bourdier Richard Lipscomb, Barrie Edgar. Although the band originated from Baton Rouge, they performed in Eastern Texas, honing their skills with cover songs, drawing influence from the British Invasion groups the Beatles and the Rolling Stones. With the subsequent addition of George Ratzlaff the Basement Wall expanded beyond local frat house concerts to popular teen nightclubs as far as Los Angeles becoming the highest-paid cover band in the southern U. S. according to the Louisiana Entertainment Association.
A live performance by the group in 1967 at a venue in Texas called Act III is featured on the compilation album There Goes the Neighborhood, Volume 2, which showcases the Basement Wall's raw vocal harmonic and fuzz-toned guitar interpretations of popular songs including "Pretty Ballerina", "Let's Spend the Night Together", "Eleanor Rigby". In 1967, the band began writing their own original material; the group entered Robin Hood Studio in Tyler, Texas to record several demos, including their lone single, a biproduct of the Texas garage rock scene, the Ratzlaff-penned "Never Existed". The recording sessions were produced by Wes Farrell, who composed the McCoys' number one hit "Hang On Sloopy", the guitar arrangements were provided by Ronnie "Mouse" Weiss of Mouse and the Traps, its B-side "Taste of a Kiss" was another Ratzlaff composition is a pop rock number marked by up-tempo keyboards. The single became a regional hit upon release in June 1967, an album was released. Regardless, much of the Basement Wall's material was released on The Incredible Sound of the Basement Wall in 1985 on Cicadelic Records.
In 1968, Bourdier retired from the music industry after getting married. Although the group did replace him with Duke Bardwell, who toured with Elvis Presley, they could not recapture the chemistry and disbanded in the year. Ratzlaff resurfaced with the blues rock outfit Potliquor, scoring a national hit with the song "Cheer" in 1972. Since its initial release, "Never Existed" has been reissued on Boulders, Volume 10, Volume 1, Relics, Volume 2. An alternate version of the song appears on Garage Beat'66 Volume 5: Readin' Your Will. In 2005, the Basement Wall held a reunion concert with the original lineup in honor of their induction into the Louisiana Entertainment Hall of Fame. Richard Lipscombe - lead guitar, bocals Terry Bourdier - bass guitar George Ratzlaff - lead vocals, rhythm guitar, keyboards Barrie Edgar - drums Duke Bardwell - bass guitar "Never Existed" b/w "Taste of a Kiss"