Mechanism design

Mechanism design is a field in economics and game theory that takes an objectives-first approach to designing economic mechanisms or incentives, toward desired objectives, in strategic settings, where players act rationally. Because it starts at the end of the game goes backwards, it is called reverse game theory, it has broad applications, from politics to networked-systems. Mechanism design studies solution concepts for a class of private-information games. Leonid Hurwicz explains that'in a design problem, the goal function is the main "given", while the mechanism is the unknown. Therefore, the design problem is the "inverse" of traditional economic theory, devoted to the analysis of the performance of a given mechanism.' So, two distinguishing features of these games are: that a game "designer" chooses the game structure rather than inheriting one that the designer is interested in the game's outcomeThe 2007 Nobel Memorial Prize in Economic Sciences was awarded to Leonid Hurwicz, Eric Maskin, Roger Myerson "for having laid the foundations of mechanism design theory".

In an interesting class of Bayesian games, one player, called the "principal", would like to condition his behavior on information known to other players. For example, the principal would like to know the true quality of a used car, he cannot learn anything by asking the salesman, because it is in the salesman's interest to distort the truth. However, in mechanism design the principal does have one advantage: He may design a game whose rules can influence others to act the way he would like. Without mechanism design theory, the principal's problem would be difficult to solve, he would have to consider all the possible games and choose the one that best influences other players' tactics. In addition, the principal would have to draw conclusions from agents. Thanks to mechanism design, the revelation principle, the principal only needs to consider games in which agents truthfully report their private information. A game of mechanism design is a game of private information in which one of the agents, called the principal, chooses the payoff structure.

Following Harsanyi, the agents receive secret "messages" from nature containing information relevant to payoffs. For example, a message may contain information about their preferences or the quality of a good for sale. We call this information the agent's "type". Agents report a type to the principal that can be a strategic lie. After the report, the principal and the agents are paid according to the payoff structure the principal chose; the timing of the game is: The principal commits to a mechanism y that grants an outcome y as a function of reported type The agents report dishonestly, a type profile θ ^ The mechanism is executed In order to understand who gets what, it is common to divide the outcome y into a goods allocation and a money transfer, y =, x ∈ X, t ∈ T where x stands for an allocation of goods rendered or received as a function of type, t stands for a monetary transfer as a function of type. As a benchmark the designer defines what would happen under full information. Define a social choice function f mapping the type profile directly to the allocation of goods received or rendered, f: Θ → X In contrast a mechanism maps the reported type profile to an outcome y: Θ → Y A proposed mechanism constitutes a Bayesian game, if it is well-behaved the game has a Bayesian Nash equilibrium.

At equilibrium agents choose their reports strategically as a function of type θ ^ It is difficult to solve for Bayesian equilibria in such a setting because it involves solving for agents' best-response strategies and for the best inference from a possible strategic lie. Thanks to a sweeping result called the revelation principle, no matter the mechanism a designer can confine attention to equilibria in which agents truthfully report type; the revelation principle states: "To every Bayesian Nash equilibrium there corresponds a Bayesian game with the same equilibrium outcome but in which players truthfully report type." This is useful. The principle allows one to solve for a Bayesian equilibrium by assuming

Xenosaga I & II

Xenosaga I & II is a role-playing video game co-developed by Monolith Soft and Tom Create, published by Namco for the Nintendo DS. A spin-off of the Xenosaga trilogy and forming part of the Xeno metaseries, Xenosaga I & II retells the events Xenosaga Episode I and Xenosaga Episode II while expanding on its characters and narrative. Displayed from an angled two-dimensional perspective, Xenosaga I & II makes use of a turn-based battle system with elements carried over from the main Xenosaga games. Xenosaga I & II, Monolith Soft's first portable video game title, began development in 2005 following the completion of Xenosaga: The Animation; the scenario and supervised by series creator Tetsuya Takahashi, was intended to retell the story of the two games while incorporating events, cut. The game was released in Japan in March 2006. Upon release, it received positive reviews from critics, but was not commercially successful. Xenosaga I & II is a role-playing video game which retells the events of Xenosaga Episode I and its direct sequel Episode II.

Cutscenes and the in-game environments and character sprites are displayed on the Nintendo DS console's top screen, with events outside still animated cutscenes taking place from an angled top-down perspective using two-dimensional graphics. Additional information is displayed on the DS's bottom screen. Environments can be explored, with breakable chests holding consumable items and accessories. Shops within the levels can be used to purchase items and equipment using in-game currency. Special EVA structures within the environment can be used to recover health points and a type of skill point called ether points. Characters are able to both enter story-based dungeons. During the course of the story, the player receives emails through the U. M. N. Service, used to store the game's glossary, a store of information on the world and characters. Unlike the original versions, Xenosaga I & II features random encounters within the environment, with enemies only appearing in the battle arena. During battle, the battle arena is displayed on the DS's top screen while commands and party status is displayed on the bottom screen.

Battles are governed by a turn-based battle system similar to the main Xenosaga games. Battles take plates on a 5x6 grid divided between the enemy party. During their turn, a character can move to any part of their half of the grid; the party's statistics are divided between HP, EP, drained by using Ether abilities, attack points when a party member performs an attack, a boost count gauge, filled when an enemy attacks. Each character is given two actions per turn, with one physical and one magical attack per character; when a character has three AP available, they can attack twice and trigger a special cinematic attack which deals high damage. The Boost meter, once filled, grants either side additional turns. In addition to independent movements, the party can create formations, with specific formations triggering different status buffs such as regenerating HP or AP. New formations are acquired through the course of the game, are specific to characters. Following each battle, characters gain both experience points and ability points.

Each character's equipment can be enhanced through the combined effects of assigning types of equipment and items or accessories to a particular character, strengthening their abilities. In addition to standard battles, characters have access to mechs with their own move sets and abilities, with basic mechanics shared with normal battles. Early development work for Xenosaga I & II began following the completion of Xenosaga: The Animation in 2005, although plans existed while the anime was in development. Xenosaga I & II was co-developed by Xenosaga series developer Monolith Soft and external studio Tom Create, it was Monolith Soft's first time developing a portable game, as they had only worked on home console titles. The script was written by Yuichiro Takeda, whose previous work included both Xenosaga: The Animation and Xenosaga CD dramas; the script was based on drafts by series creator Tetsuya Takahashi, who supervised the writing process. Staff related to multiple video game and anime projects took part, with their previous work including Xenosaga: The Animation.

Character designs were redrawn by Hiroshi Takeuchi, who had done artwork for Cowboy Bebop and My-HiME. The drawing director was Ai Kikuchi, who had worked on the anime adaptation of the Star Ocean: The Second Story manga. Cutscene director Hiroyuki Okawa had worked on both Xenosaga: The Animation and Mobile Suit Gundam SEED. Coloring for cutscene artwork was done by Studio Deen; the music was composed by Kousuke Yamashita, who had worked on both Xenosaga: The Animation and the Nobunaga's Ambition series. Due to the size of the narrative, the game used a 2D art style. Voice acting was limited to victory quotes after successful battles, with the rest of the story communicated with text. Takeda was first shown the project while still working on Xenosaga: The Animation, a work load he estimated at six months. Once work on the anime had finished and Takahashi began work on the script. Takahashi created the draft based on his original plans for the Xenosaga storyline, which had needed substantial alteration for the original Episode I and Episode II due to both design and time limitations.

The scenario for Episode I required little alteration as it was unaltered from Takahashi's initial draft. For Episode II, more substantial alterations were made such as re

Kaiserliche Werft Danzig 1650

Number 1650 was the sole example of a unique seaplane design produced for the flying service of the Imperial German Navy during the First World War. From 1916 onwards, the Kaiserliche Werften produced a range of training seaplanes for the Navy, in order to free the nation's major seaplane manufacturers to produce front-line types. During the closing stages of the war, the Kaiserliche Werft Danzig and Kaiserliche Werft Wilhelmshaven produced a small number of front-line types as well, including this machine. Number 1650 was an armed reconnaissance seaplane equipped with radio equipment capable of transmission and reception, therefore gaining the naval CHFT classification. Data from Kroschel & Stützer 1994, p.165General characteristics Crew: Two and observer Powerplant: 1 × Mercedes D. IV, 160 kW 1 × trainable 7.9 mm machine gun Gray, Peter. German Aircraft of the First World War. London: Putnam. Kroschel, Günter. Die Deutschen Militärflugzeuge 1910–1918. Herford: Verlag E. S. Mittler & Sohn. Nowarra, Heinz J..

Marine Aircraft of the 1914–1918 War. Letchworth, Harts: Harleyford Publications