Why Technical English

Game Theory in Computer Science

January 25, 2011
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        By Galina Vitkova  

Computer science or computing science (sometimes abbreviated CS) is the study of the theoretical foundations of information and computation and of practical techniques for their implementation and application in computer systems. It concerns the systematic study of algorithmic processes that describe and transform information. Computer science has many sub-fields. For example, computer graphics, computational complexity theory (studies the properties of computational problems), programming language theory (studies approaches to describing computations), computer programming (applies specific programming languages to solve specific problems), and human-computer interaction (focuses on making computers universally accessible to people) belong to such very important sub-fields of computer science. 

Game theory has come to play an increasingly important role in computer science. Computer scientists have used games to model interactive computations and for developing communication skills. Moreover, they apply game theory as a theoretical basis to the field of multi-agent systems (MAS), which are systems composed of multiple interacting intelligent agents (or players). Separately, game theory has played a role in online algorithms, particularly in the k-server problem.

Interactive computation is a kind of computation that involves communication with the external world during the computation. This is in contrast to the traditional understanding of computation which assumes a simple interface between a computing agent and its environment. Unfortunately, a definition of adequate mathematical models of interactive computation remains a challenge for computer scientists. 

 
An online algorithm is the one that can process its input piece-by-piece in a serial mode, i.e. in the order that the input is fed to the algorithm, without having the entire input available from the start of the computation. On the contrary, an offline algorithm is given the whole problem data from the beginning and it is required to output an answer which solves the problem at hand.    

An animation of the quicksort algorithm sortin...

Image via Wikipedia

 (For example, selection sort requires that the entire list be given before it can sort it, while insertion sort doesn’t.) As the whole input is not known, an online algorithm is forced to make decisions that may later turn out not to be optimal. Thus the study of online algorithms has focused on the quality of decision-making that is possible in this setting.

The Canadian Traveller Problem exemplifies the concepts of online algorithms. The goal of this problem is to minimize the cost of reaching a target in a weighted graph where some of the edges are unreliable and may have been removed from the graph. However, the fact that an edge was removed (failed) is only revealed to the traveller when she/he reaches one of the edge’s endpoints. The worst case in study of this problem is simply a situation when all of the unreliable edges fail and the problem reduces to the usual Shortest Path Problem. This 

Johnson's algorithm for transforming a shortes...

Image via Wikipedia

 

 problem concerns detecting a path between two vertices (or nodes) of the graph such that the sum of the weights of its edges is minimized. An example is finding the quickest way to get from one location to another on a road map. In this case, the nodes represent locations, the edges represent segments of road and are weighted by the time needed to travel that segment.

The k-server problem is a problem of theoretical computer science in the category of online algorithms. In this problem, an online algorithm must control the movement of a set of k servers, represented as points in a metric space, and handle requests that are also given in the form of points in the space. As soon as a request arrives, the algorithm must determine which server to be moved to the requested point. The goal of the algorithm is to keep the total distance all servers move small, relative to the total distance the servers could have moved by an optimal adversary who knows in advance the entire sequence of requests.

The problem was first posed in 1990. The most prominent open question concerning the k-server problem is the so-called k-server conjecture. This conjecture states that there is an algorithm for solving the k-server problem in an arbitrary metric space and for any number k of servers. The special case of metrics in which all distances are equal is called the paging problem because it models the problem of page replacement algorithms in memory caches. In a computer operating system that uses paging for virtual memory management, page replacement algorithms decide which memory pages to page out (swap out, write to disk) when a page of memory needs to be allocated. Paging happens when a page fault occurs and a free page cannot be used to satisfy the allocation, either because there are none, or because the number of free pages is lower than a set threshold. 

 

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Tactical Media and games

December 1, 2010
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Composed by Galina Vitkova

  

Introductory notes

Tactical media is a form of media activism that uses media and communication technologies for social movement and privileges temporary, hit-and-run interventions in the media sphere. Attempts to spread information not available by mainstream news are also called media activism. The term was first introduced in the mid-1990s in Europe and the United States by media theorists and practitioners. Since then, it has been used to describe the practices of a vast array of art and activist groups. Tactical media also shares something with the hacker subculture, and in particular with software and hardware hacks which modify, extend or unlock closed information systems and technologies.

Tactical Media in Video Games

Video games have opened a fully new approach for tactical media artists. This form of media allows a wide range of audiences to be informed of a specific issue or idea. Some examples of games that touch on Tactical Media are Darfur is Dying and September 12. One example of a game design studio that works in tactical media is TAKE ACTION games (TAG). The video game website www.newsgaming.com greatly embodies the idea of tactical media in video games. Newsgaming coins this name as a new genre that brings awareness of current news related issues based on true world events apposed to fantasy worlds that other video games are based upon. It contributes to emerging culture that is largely aimed at raising awareness about important matters in a new and brilliant approach.

Other examples of tactical media within video games include The McDonald’s Game. The author of this game takes information from the executive officers of McDonalds and giving it to the public by informing people about how McDonalds does its business and what means it uses to accomplish it.

Chris Crawford’s Balance of the Planet, made in 1990, is another example of tactical media, in which the game describes environmental issues.

Darfur is Dying description   

Camp of Darfuris internally displaced by the o...

Image via Wikipedia

Origination

It is a browser game about the crisis in Darfur, western Sudan. The game won the Darfur Digital Activist Contest sponsored by the company mtvU ((Music Television for Universities campus)). Released in April 2006, more than 800,000 people had played it by September. It is classified as a serious game, specifically a newsgame.
The game design was led by Susana Ruiz (then a graduate student at the Interactive Media Program at the School of Cinematic Arts at the University of Southern California) as a part of TAKE ACTION games. In October 2005 she was attending the Games for Change conference in New York City, where mtvU announced that they, in partnership with other organizations, were launching the Darfur Digital Activist Contest for a game. The game should also be an advocacy tool about the situation in the Darfur conflict. Since mtvU offered funding and other resources, Ruiz decided to participate in this project.
Ruiz formed a design team and spent two months creating a game design document and prototype. The team spent much of the design phase talking to humanitarian aid workers with experience in Darfur and brainstorming how to make a game that was both interesting to play and was an advocacy tool. The Ruiz team’s beta version was put up for review by the public, along with the other finalists, and was chosen as the winner. The team then received funding to complete the game. The game was officially released at a Save Darfur Coalition rally on 30 March 2006.
Map of Darfur, Sudan (
Image via Wikipedia

 

Gameplay

The game begins with the player choosing a member of a Darfuri family that has been displaced by the conflict. The first of the two modes of the game begins with the player controlling the family member, who travelled from the camp to a well and back, while dodging patrols of the janjaweed militia. If captured, the player is informed what has happened to his/her selected character and asked to select another member of the family and try again. If the water is successfully carried back to the camp, the game switches into its second mode – a top down management view of the camp, where the character must use the water for crops and to build huts. When the water runs out the player must return to the water fetching level to progress. The goal is to keep the camp running for seven days.

 

Original caption states,

Image via Wikipedia

 Reception of the game

The game has been reported by mainstream media sources such as The Washington Post, Time Magazine, BBC News and National Public Radio. In an early September 2006 interview, Ruiz stated that it was difficult to determine success for a game with a social goal, but affirmed that more than 800,000 people had played it 1.7 million times since its release.  Moreover, tens of thousands of them had forwarded the game to friends or sent a letter to an elected representative. As of April 2007, the game has been played more than 2.4 million times by over 1.2 million people worldwide.

 The game has been the focus of debate on its nature and impact. Some academics, interviewed by the BBC on the game, stated that anything that might spark debate over Darfur and issues surrounding is a clear gain for the advocates. The others thought that the game oversimplified a complex situation and thus failed to address the actual issues of the conflict.  The game was also criticized for the sponsorship of mtvU, raising the possibility that the game might seem like a marketing tool for the corporation. The official site does not use the word “game”, but refers to Darfur is Dying as a “narrative based simulation.”

 

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Online game playing

October 25, 2010
3 Comments
By  P. B.

There are a lot of servers on the Internet that provide playing games online. The playing is very easy and many users who have only basic knowledge about computers and the Internet can play these games. The most common way of starting to play is to open the Internet and visit the Google page.   Then in the box for searching write two words: online games and Google immediately offers you many servers, e.g. www.onlinegames.net, www.freeonlinegames.com or Czech pages www.super-games.cz etc. Each server proposes many various games of different sorts. There you may find games for boys, girls, kids, most played games, new games, and others. Or you can select games by a subject, i.e. adventure games, sports games, war games, erotic or strategic games, etc.         

Assigning a path for Leviathan

Image by Alpha Auer, aka. Elif Ayiter via Flickr

Many games have own manual how to play, so the second step is to study the manual. Depending on the subject of a game the user must use, for example, the key Right Arrow to go forward, Left Arrow – to go back, PgUp – to go up, Ctrl – to shoot. It is very easy to understand how to play and recognize what is the goal of the game, e.g. to have maximum points, to kill everything that moves or to be the first in the end. These games are rather simple-minded, but some people become too addicted to them trying to improve their best performance. Sometimes they spend hours before the screen every day and don´t have any idea about time.  

I have tried four different servers and about six different games. In my opinion these games are very easy and for me boring, but for younger users or for people who are bored right now the games can be interesting. However, the most important thing (in my view) is that two of tested servers were infected (my computer warned me that the pages are dangerous and can contain malware, spyware or viruses). My friends, who have problems with their computers in this sense, want me to repair their computer – maybe that is the reason why I don’t like playing games online directly on the Internet.

Quake3 + net_server
Image by [Beta] via Flickr

 

On the other side, I have also tried the game Quake 3 (game demo – not through the Internet, but after installing this game on my computer) and I can affirm that it was  pretty interesting.

 

Quake 3 Arena is a really shooting game. There is no other goal than to kill all other players (but in other versions like Team death match or Capture the flag two teams fight against each other). The player can choose the level of demandingness (from easy to hard) and various places. Quake 3 Arena is the mode where the player fights in the Arena against computer controlled bots (Artificial Intelligent fighters). 

The fighters do battle equipped with various weapons as follows:

  • Gauntlet – a basic weapon for very near fight, usually used only when the player does not have other gun;
  • Machinegun – a thin gun, again applied only when a better gun is not in equipment;
  • Shotgun – a weapon for near fight, 1 shoot every 1 second;
  • Grenade Launcher – shoots grenades;
  • Rocket Launcher – a very popular weapon because its usage is very easy and impact is huge; But the flight of a rocket is slow, so the players get used to shooting at the wall or floor because the rocket has big dispersion;
  • Lighting Gun – an electric gun, very effective because can kill the rival in 2 seconds;
  • Rail gun – a weapon for long distance, very accurate, but has short frequency;
  • Plasma Gun – shoots plasma pulse;
  • BFG10K – the most powerful weapon, but the worst-balanced, and for this reason is not often used by players (BFG = Bio Force Gun).

It is important for the players to find and acquire the armor – the maximum is 200 points armor. The armor provides protection, which absorbs 2/3 of damage. Similarly the players can control their health (from the beginning they have 125 points, which make 100%, and can reach maximum 200 points).

Sometimes (depending on the game) additional features are involved – a Battle suit, Haste (makes movement and shooting twice faster within 30 seconds), Invisibility (for 30 seconds), Medkit, Teleporter (the player is moved to a casual place), Regeneration, Flight (during 60 seconds) and so on.  

  

 


Renewables are becoming more and more popular

January 23, 2010
3 Comments
Composed by Galina Vitkova

REN21 (Renewable Energy Policy Network for the 21st Century) has just issued the newest information about the current renewable policy and its realisation in the form of Renewables Interactive Map (beta-version). The Map can be found on the REN21 website, at http://www.ren21.net/mapThe map contains a great deal of information on renewable energy, including support policies, expansion targets, current shares, installed capacity, current production, future scenarios, policy pledges, etc. It enables you to immediately gain by simple clicking on the country of your interest, depicted on the world geographic map, the current information about:

  • Renewables in General:
  • ♦ Policies (feed-in tariff, investment tax credits, net metering, etc)
  • ♦ Targets (final energy, primary energy, electricity, heating/cooling, etc)
  • ♦ Scenarios (before 2020, after 2020 up to 2050)
  • ♦ Others
  • Statistics (global and for individual participating countries) on geothermal energy, wind energy, solar energy, biofules (mainly ethanol)
  • Information about all kind of renewable which the country concerns (energy of wind, solar, hydro, geothermal, biomass), again for the world and for world regions
  • Technologies in use
  • And others

So the map serves as a central access-point to current renewable energy information, which is very comfortable. Moreover, you will find unknown for you concepts in the glossary accessed from the map.

REN21 has already ensured authentic information for several years, in particular through its Renewables Global Status Report. A new tool, the Renewables Interactive Map is intended to trail more closely the dynamic development of renewable energy production and market development. Furthermore, it provides disaggregated information for particular countries and technologies (see aggregated information on the topic at this blog too, About renewables position just now ).

Studying renewable energy information you improve your technical English, enjoying competent technical texts. Moreover, at the same time you gain very advantageous and comprehensive information about things which we all depend on.

Find below aggregated statistics which denote:

  • Geothermal  energy  (cumulative installed geothermal power capacity in MW)
  • Solar  energy  (cumulative  installed  photovoltaic (PV) power in MW)
  • Wind energy (cumulative  installed capacity  of wind turbines in MW)
  • Fuel ethanol (production in thousand tonnes oil equivalent).

Study the statistics of worldwide renewables adopted from http://www.bp.com/liveassets/bp_internet/globalbp/globalbp_uk_english/reports_and_publications/statistical_energy_review_2008/STAGING/local_assets/2009_downloads/renewables_section_2009.pdf.

Notice the column „Change 08 over 07“.  It demonstrates that in 2008 capacity of renewables installations is increase in comparison with 2007.   For example, production of ethanol in the USA increased by 42.0 % and makes 52.2 % world production of ethanol. In Europe the production increased by 50.8, but makes only 3.8 % world production of this biofuel. Statistics about usage of solar energy usage in Europe are of particular interest. For example, total increase of cumulative  installed  photovoltaic (PV) power counts up to 69.1 %, where Germany increased its solar  installed  PV power by 37.5 %(40,9 % of world total) and Spain had the growth of its solar  installed  PV power by 422.2 % (24.5 % of world total).

Geothermal  energy (MW)

2008

Change 08 over 07
Share of total
Indonesia

1 042.5

6.1 %

10.0 %

Italy

810.5

– 

7.7 %

Japan

537.3

5.1 %

Mexico

964.5

0.5 %

9.2 %

New Zealand

586.6

24.4 %

5.6 %

Philippine

1 780.0

18.9 %

USA

2 998

2.1 %

28.6 %

Total

10 469.0

4.2 %

100 %

  

Solar energy (MW)

  

2008

 

Change 08 over 07
 
Share of total

North America

1 226.7

39.9 %

9.1 %

incl.:  USA

1 172.5

41.2 %

8.7 %

Europe (without Russian Federation)

9 614.9

92.3 %

71.5 %

 incl.: Germany

5 498.0

37.5 %

40.9 %

 incl.:  Spain

3 291.2

422.2 %

24.5 %

Others

2 603.3

25.1 %

19.4 % 

incl.:  Japan

2 148.9

12.0 %

16.0 %

Total

13 444.9

69.1 %

100 %

 

Wind  energy (MW)

2008

Change 08 over 07
Share of total
North America  

27 940

48.6 %

22.9 %

incl.:  USA

25 237

49.5 %

20.7 %

Europe+Euroasia

65 998

68.2 %

54.0 %

incl.:    Germany

23 933

7.4 %

19.6 %

incl.:   Spain

16 543

12.4 %

13.5 %

Asia Pacific

26 446

59.8 %

21.6 %

incl.:  China

12 121

106.3%

9.9 %

incl.:  India

9 655

23.1 %

7.9 %

Total

122 158

29.9 %

100 %

Fuel  ethanol (thousand tonnes)

2008

Change 08 over 07
Share of total

North America

18 154

42.0 %

52.2 %

incl.:  USA

17 460

41.3 %

50.2 %

South America

13 723

19.7 %

39.4 %

incl.:  Brasilia

13 549

20.0 %

38.2 %

Europe

1337

50.8 %

3.8 %

Asia Pacific

1 586

10.4 %

4.6 %

incl.:  China

1 021

– 2.4 %

2.9 %

Total

34 800

30.9 %

100 %

        

Note: About REN21

REN21 (Renewable Energy Policy Network for the 21st Century)  is a global policy network that provides a forum for international leadership on renewable energy. Its goal is to encourage the policy of development and the rapid expansion of renewable energies in developing and industrialised economies.

 

 


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