A* search algorithm

In computer science, A* (pronounced as "A star" ( listen)) is a computer algorithm that is widely used in pathfinding and graph traversal, the process of plotting an efficiently traversable path between multiple points, called nodes. Noted for its performance and accuracy, it enjoys widespread use. However, in practical travel-routing systems, it is generally outperformed by algorithms which can pre-process the graph to attain better performance, although other work has found A* to be superior to other approaches.

Peter Hart, Nils Nilsson and Bertram Raphael of Stanford Research Institute (now SRI International) first described the algorithm in 1968. It is an extension of Edsger Dijkstra's 1959 algorithm. A* achieves better performance by using heuristics to guide its search.

History

In 1968, AI researcher Nils Nilsson was trying to improve the path planning done by Shakey the Robot, a prototype robot that could navigate through a room containing obstacles. This path-finding algorithm, that Nilsson called A1, was a faster version of the then best known method, Dijkstra's algorithm, for finding shortest paths in graphs. Bertram Raphael suggested some significant improvements upon this algorithm, calling the revised version A2. Then Peter E. Hart introduced an argument that established A2, with only minor changes, to be the best possible algorithm for finding shortest paths. Hart, Nilsson and Raphael then jointly developed a proof that the revised A2 algorithm was optimal for finding shortest paths under certain well-defined conditions.

Suzuki Alto

The Suzuki Alto (スズキ・アルト) is a kei car built by Suzuki. Its selling points have long included a low price and good fuel economy. The model, currently in its eighth generation, was first introduced in 1979 and has been built in many countries worldwide. The Alto badge has often been used on different cars in Japan and in export markets, where it is considered a city car.

First generation (1979–1984)

The first generation (SS30V/40V), introduced in May 1979, was a three-door cargo version of the Fronte passenger car, equipped with a folding rear seat. Front suspension comprised coils struts, with leaf springs at the back. The steering was of the recirculating ball type, and four-wheel drums were used. On introduction, the Alto received the T5B two-stroke 539 cc (32.9 cu in) (SS30) three-cylinder engine, producing 28 PS (21 kW) at 5,500 rpm. The Alto was a "micro sensation" when introduced, largely due to its rock bottom price of ¥470,000 (circa $1,900 in 1979, at a time when the cheapest Ford Pinto cost $4,999 in the US). This low price was made possible by a number of Japanese special concessions for commercial vehicles: most notably, the engine did not require twin catalysts. Two less doors provided another saving, as did the exemption from commodity tax. The Alto's success changed the kei-car market, and other producers such as Subaru (with the "Family Rex") quickly followed suit with cut-price "commercial" vehicles that were really intended for private use. The Alto helped Suzuki move into seventh place in Japanese production for cars and trucks.

Agency for Science, Technology and Research

The Agency for Science, Technology and Research (Abbreviation: A*STAR; Chinese: 新加坡科技研究局) is a statutory board under the Ministry of Trade and Industry of Singapore. The Agency was established in 1991 to foster scientific research and talent for a knowledge-based Singapore.

History

Established in 1991 as the former National Science and Technology Board (NSTB), A*STAR was established with the primary mission to raise the level of science and technology in Singapore.

Leadership

The current chairman of A*STAR is Mr. Lim Chuan Poh. He was formerly the Permanent Secretary (Education) and the Chief of Defence Force. Mr Lim took over the reins of A*STAR from Mr. Philip Yeo, who later became Chairman of SPRING Singapore, on 1 April 2007.

The scientific leadership includes Tan Chorh Chuan, George Radda, Sydney Brenner, David Lane, Charles Zukoski and used to include Prof Low Teck Seng. Prof Low Teck Seng left A*Star on 19 July 2012 to join the National Research Foundation of the Prime Minister's Office.