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Redes
2006
Índice
1. Redes P2P
Redes
2. Redes ad-hoc
3. Grid computing
4. Redes cooperativas
5. Redes sociales
6. Problemas y soluciones
Definición
Redes P2P
• Un sistema peer-to-peer (p2p) es un sistema distribuido sin
ningún control centralizado y donde la funcionalidad de cada
nodo es idéntico.
“Single servants are less powerful than a single server
but the collective of many servants is more powerful
than any single server” – by Daniel Stephen Rule
Redes P2P
Definiciones
Preocupación sobre la red
Definiciones P2P
Preocupación sobre la aplicación
Redes P2P
Definiciones
Redes completamente descentralizadas con estructuras
no-jerárquicas y comunicación simétrica - Stoica et al.
Preocupación sobre la red
Definiciones P2P
Preocupación sobre la aplicación
Redes P2P
Definiciones
Los sistemas P2P acentúan la cooperación entre entidades
(conocidas como Peers) que son esencialmente iguales y que se
proporcionan servicios entre ellas. P2P acentúa la descentralización,
la resistencia y la explotación de recursos de la red - Coulson.
Preocupación sobre la red
Definiciones P2P
Preocupación sobre la aplicación
Redes P2P
Definiciones
Elementos relacionados que se aprovechan de los recursos
disponibles de la red - Shirky
Preocupación sobre la red
Definiciones P2P
Preocupación sobre la aplicación
Redes P2P
Topología de la red
Redes P2P
Topologías P2P
Propiedades


No existe un control central=> Sistema distribuido
No existe jerarquía
Redes P2P







Todos los nodos son a clientes y servidores
La comunicación entre nodos es simétrica
No existe una visión global
Escalabilidad
Disponibilidad para cualquier peer
Los peers son autónomos
Sistema globalmente poco fiable

Aspectos de robustez y seguridad
Avances
Que ha permitido llegar hasta este punto?
Redes P2P
Historia / Evolución
(Computación)
Computación y
Comunicación Ubicua
Cultura / Sociedad
(Servicios / Intercambio
de ficheros)
Gran extensión de
conexión a Internet
Comunicación
/ Colaboración
Comunicaciones de
banda ancha, Wireless,
nuevos tipos de Redes.
Arquitectura
Algoritmos
Que posibilidades ofrece?
Aprovechar la potencia del
ordenador en casa y la
oficina
Intercambio usuariousuario, minimiza los
vínculos con intermediarios
Comunicaciones y
colaboración
Incremento en la
descentralización de Internet
Gran escalabilidad, mejor
accesibilidad
Estados descentralizados
Mejoras en la escalabilidad,
disponibilidad y anonimato
Taxonomia
Redes P2P
P2P Applications
Parallel
Content and
file management
Compute Compo- Content
Intensive nentized exchange
File
system
Collaboration
Filtering, Instant
mining
message
Shared
apps
Games
Ejemplos

Redes P2P







Aplicaciones de intercambio de ficheros (Naptser,…)
Bases de datos distribuidas
Computación distribuida (SETI,…)
Comunicación distribuida (AOL Instant Messaging,…)
Colaboración (Groove)
Juegos distribuidos
Redes Ad-hoc
Etc.
Groove

Redes P2P



Aplicación Windows de colaboración.
Funciona contra un servidor central.
 Empresa Groove Networks.
Servicios de colaboración:
 Intercambio de ficheros
 Intercambio de mensajes o notas
 Chat en modo texto y voz
 Navegación Web sincronizada
 Agenda y calendario
Es un sistema extensible
Groove


Redes P2P




Integra varias aplicaciones en una.
Facilidad de uso.
Piloto de sala virtual de discusión en tiempo real.
Navegación individual o sincronizada.
Para colaborar hay que estar conectado.
 Se pueden distribuir mensajes a usuarios que no están
conectados
 Los mensajes pasan por el servidor
Se pueden definir servicios de colaboración directa entre
usuarios.
VIDEO: grv-sf
SETI

Redes P2P



Es un proyecto de la Universidad de Berkeley para buscar
vida extraterrestre inteligente.
El método:
 Análisis de ondas electromagnéticas provenientes del
espacio exterior, obtenidas de radiotelescopios.
La técnica :
 Buscar patrones, series, repeticiones en el ruido de fondo
captado.
 El sistema está formado por un grupo de ordenadores
centrales que reciben las emisiones de los telescopios y
dividen la información recibida en bloques
 Los bloques se entregan a la red de PCs para buscar
resultados parciales y luego ensamblarlos
• Utiliza ciclos inactivos de CPU de los ordenadores a
través de Internet
Con este sistema se procesa más del doble que con el
ordenador más potente
 ASCI White: 12 Teraflops/s (110 millones de $)
 [email protected]: 31 Teraflops/s (0,5 M$, 3,3 millones de PCs)
Redes P2P
SETI
Redes P2P
SETI
VIDEO: Seti2401
RADIO: radio_network_comercial
Node versus Agent
Redes P2P

An agent is one that is capable of flexible autonomous
action in order to meet its design objectives, where
flexibility means three things:




Pro-activeness: the ability of exhibit goal-directed
behavior by taking the initiative
Reactivity: the ability of percept the environment, and
respond in a timely fashion to changes that occur in it
Social ability: the ability of interaction with other agents
(include human)
A node follows a protocol established in the system.
Distribución de contenido en P2P

Beneficios:

Redes P2P


Mejora dramáticamente la velocidad => Escalable
Servidores con pocos requerimientos => Barato
Desafíos:





Requiere incentivas para la cooperación
Seguridad
Manejabilidad
Variabilidad en los anchos de banda
Necesidad de algoritmos distribuidos
Redes P2P
Topologías
• Centralized service location, e.g. Napster
• Flooded request model / Distributed service
location with flooding, e.g. Gnutella
• Document routing model / Distributed search
hashing / Distributed service location with
hashing, e.g. Pastry, Chord
• BitTorrent
Redes P2P
Centralized service location
Redes P2P
Distributed service location with flooding
Redes P2P
Gnutella protocol
Redes P2P
Gnutella protocol
Redes P2P
Kazaa un Gnutella jerarquizado
Redes P2P
Distributed search hashing
• Internet-scale distributed hash tables
– Equally valuable to large-scale distributed
systems?
• Peer-to-peer systems
– CAN, Chord, Pastry, …
• Large-scale storage management systems
– Publius, OceanStore, CFS …
• Mirroring on the Web
Redes P2P
DHT Step 1: The Hash
Redes P2P
DHT Step 2: Routing
Redes P2P
Pastry
• Completely decentralized, scalable, and selforganizing
• Seeks to minimize the distance messages travel,
according to a scalar proximity metric like the
number of IP routing hops
• In a Pastry network,
– Each node has a unique id, nodeId
– Presented with a message and a key, Pastry node
efficiently routes the message to the node with a
nodeId that is numerically closest to the key
Redes P2P
Pastry: NodeId
Redes P2P
Pastry: Routing
Chord: System Model

Load balance:
Redes P2P


Decentralization:


The cost of a Chord lookup grows as the log of the number of nodes, so
even very large systems are feasible.
Availability:


Chord is fully distributed: no node is more important than any other.
Scalability:


Chord acts as a distributed hash function, spreading keys evenly over the
nodes.
Chord automatically adjusts its internal tables to reflect newly joined nodes
as well as node failures, ensuring that, the node responsible for a key can
always be found.
Flexible naming:

Chord places no constraints on the structure of the keys it looks up.
Chord: System Model
Redes P2P

The application interacts with Chord in two main ways:

Chord provides a lookup(key) algorithm that yields the IP
address of the node responsible for the key.

The Chord software on each node notifies the application of
changes in the set of keys that the node is responsible for.
Redes P2P
Chord: Scalable key Location
Definition of variables for node n, using m-bit identifiers.
Redes P2P
Chord: Scalable key Location
(a) The finger intervals associated with node 1. (b) Finger tables and
key locations for a net with nodes 0, 1, and 3, and keys 1, 2, and 6.
Redes P2P
Chord: Node joins
(a) Finger tables and key locations after node 6 joins. (b) Finger table
and key locations after node 1 leaves. Changed entries are shown in
black , and unchanged in gray.
Redes P2P
Chord
Redes P2P
Chord routing
Redes P2P
Chord routing
Redes P2P
Chord node insertion
Redes P2P
Chord node insertion (cont’d)
Redes P2P
Chord node insertion (cont’d)
El problema de los free riders
Redes P2P

From Wikipedia, the free encyclopedia:
“In economics and political science free riders are actors
who consume more than their fair share of a resource, or
shoulder less than a fair share of the costs of its production.
The free rider problem is the question of how to prevent
free riding from taking place, or at least limit its negative
effects.”
BitTorrent

Usa ideas básicas de la teoría de juegos para eliminar
el problema de los free-riders
Los sistemas anteriores no trataban dicho problema
Redes P2P

VIDEO: FutureOfBitTorrent
Redes P2P
BitTorrent: Dilema del prisionero
Redes P2P
BitTorrent
The main goal of BitTorrent concerning efficiency is to
be Pareto efficient, because this measure is used
often by economists as efficiency goal. By definition an
outcome of a game is Pareto efficient if there is no
other outcome that makes every player at least as well
off and at least one player strictly better off. That is, a
Pareto Optimal outcome cannot be improved upon
without hurting at least one.
In computer science terms, seeking Pareto efficiency is
a local optimization problem in which pairs of
counterparties see if they can improve their lot together,
and such algorithms tend to lead to global optima.
BitTorrent: Idea básica


Redes P2P


Cortar un fichero en diferentes piezas
Replicar diferentes piezas en diferentes peers
Tan pronto como un peer dispone de una parte, él
puede negociar con esto con otros peers
Con un poco de suerte, al final el peer será capaz de
obtener todas las piezas para completar el fichero
BitTorrent: Componentes básicos

Seed
Peer que dispone del fichero completo
Redes P2P

Leacher


A Torrent file





Peer que dispone de un fichero incompleto
Componente pasivo
Ficheros son fragmentados en piezas de 256KB
El fichero contiene una lista de SHA1 hashes de todas las piezas que
permite a los peers verificar la integridad del fichero
Típicamente hospedados en un servicio web
A Tracker



Componente activo
Permite a los peers encontrar otros peers
Devuelve una lista aleatoria de peers
BitTorrent: Algoritmo
Redes P2P



El orden en que las piezas son seleccionadas por los
diferentes peers es una parte critica para el buen
funcionamiento del sistema
Si un mal algoritmo es usado, se puede llegar a la
situación donde cada peer tiene todas las piezas que
estan disponibles y ninguno la pieza que no tiene
nadie.
Si el seed se desconecta, el fichero no puede ser
bajado complemtamente => Existe altruismo
BitTorrent: Primera pieza

Redes P2P


Inicialmente, un peer no tiene nada con que negociar
Importante que él obtenga una pieza tan pronto como
sea posible
Política: Seleccionar una pieza al azar del fichero y
bajarla
BitTorrent: Choking (estrangular)

Redes P2P




Es un mecanismo que asegura que los nodos cooperen y
elimina el problema de los nodos free-riders.
La cooperación implica que el agente de upload sub-piezas que
dispone
Choking es denegar upload a un peer
Las conexiones se mantienen abiertas así que el coste de
montar las conexiones no aumenta
Basado en el concepto de teoría de juegos:

Tit-for-tat con repetición
BitTorrent: Choking Algorithm

Redes P2P


El objetivo es tener varias conexiones bidireccionales
abiertas continuamente
Un peer siempre unchockes un número fijo de peers
(por defecto 4)
La decisión de chocke/unchoke se realiza sobre los
ratios de download, los cuales son evaluados cada 20segundos
Redes P2P
BitTorrent revisited
Redes P2P
Evolution of P2P Cooperation
Redes P2P
P2P and economic vision
Definición
Redes Ad-hoc

Del latín que significa “para esto (a propósito)”. En
general es una solución que ha sido hecho a medida. Puede
usarse también para indicar que algo es improvisado

Una red "Ad Hoc" consiste en un grupo de ordenadores que
se comunican cada uno directamente con los otros a través
de las señales de radio sin usar un punto de acceso. Las
configuraciones "Ad Hoc" son comunicaciones de tipo puntoa-punto

Particularidad esencial de las redes “Ad hoc”: el movimiento
de los nodos modifica la topología de la red. Este hecho se
ve magnificado por el corto alcance de las tecnologías
inalámbricas que suelen soportar las redes ad hoc (ej:
Bluetooth, WLAN)
02/05/06
Definición
Redes Ad-hoc

[An ad hoc network is ] a transitory association of
mobile nodes which do not depend upon any fixed
support infrastructure. [...]
Connection and disconnection is controlled by the
distance among nodes and by willingness to
collaborate in the formation of cohesive, albeit
transitory community. »
By Murphy et al. 1998
02/05/06
Uso

Imposible de predecir
Redes Ad-hoc



Imposible (difícil) de configurar


02/05/06
Emergencias
Catástrofes
Redes de sensores
Redes cooperativas
Aspectos de la redes ad hoc
Redes Ad-hoc
B
Como obtener información de A a B
cuando todo entre esos nodos esta
en movimiento?
Y que sucede con:
 Retraso
 Rendimiento
 Consumo de energía
 Caminos fiables
02/05/06
A
Comparación redes Ad-hoc y P2P

Redes Ad-hoc


P2P is based on an IP network
Ad-hoc is based on a mobile radio network
Mobile Ad-hoc and Peer-to-Peer Networks hold many
similarities concerning their



Both have to provide networking functionalities in a
completely unmanaged and decentralized environment

02/05/06
routing algorithms and
network management principles
i.e. To determine how queries (packets) are guided
through the network
Redes Ad-hoc
Comparación redes Ad-hoc y P2P
02/05/06
Redes Ad-hoc
Diferencias: redes Ad-hoc y P2P
02/05/06
Redes Ad-hoc
Similaridades: redes Ad-hoc y P2P
02/05/06
Definición
Grid Computing

From Wikipedia, the free encyclopedia:
Grid computing is an emerging computing model that
provides the ability to perform higher throughput
computing by taking advantage of many networked
computers to model a virtual computer architecture that is
able to distribute process execution across a parallel
infrastructure.
02/05/06
P2P versus Grid computing

Ambas abordan el mismo problema.
Grid Computing


Ambas realizan una misma aproximación.




Compartir recursos dentro de una comunidad virtual (pero no
en las mismas comunidades).
Creación de capas cuya estructura no corresponde con la de la
organización subyacente.
Las aplicaciones Grid generalmente usan gran cantidad de
datos y cálculos.
Los problemas que abordan las aplicaciones P2P actuales no
requieren de una gran intercambio de recursos entre los nodos.
Cada uno ha creado avances técnicos propios, pero en una
dirección complementaria


“Grid los ha dirigido en mejorar las infraestructuras pero no la
tolerancia a fallos”
“P2P los ha dirigido en mejorar los fallos pero no las
infraestructuras”
02/05/06
Grid Computing
Grid
Grids
Convergence:
Large, Dynamic, Self-Configuring Grids
 Large scale
 Intermittent resource participation
 Local control, Self-organization
 Weaker trust assumptions
 Infrastructures to support diverse
applications
 Diversity in shared resources
P2P
02/05/06
Scale & volatility
Grid Computing
PlanetLab
• Plataforma de test apra experimentar con
aplicaciones P2P y Grid.
>600 nodes, >300 sites,
– PlanteLab consorcio: + de 80 universidades,
Intel, HP
• Los usuarios ven un conjunto de Virtual
Machines donde realizar tests.
02/05/06
PlanetLab
452 nodes
sites
a162
gran
escala
450 research
projectspara
Grid Computing
• Un sistema de tests abierto y
aplicaciones P2P y servicios Grid.
02/05/06
Definition
Redes cooperativas

02/05/06
Bands of computer users in urban areas around the
world are pioneering a new type of network called
cooperative networks. When two geographically distant
devices need to communicate and cannot send
messages directly to one another, the sender asks
intermediate devices to forward its message to the
recipient or another type of action. The ownership of
the networked devices is divided among many, possibly
self-interested, individuals. Despite that the network
devices’ owners have no immediate interest in helping
one another, they frequently configure their devices to
forward traffic. The resulting collection of devices form
a cooperative network.
Ejemplo: Fon
Redes cooperativas

La idea básica aquí es que la gente está de acuerdo
en compartir de manera cooperativa su capacidad
extra de conexión de banda ancha , a cambio de
recibir acceso libre para otros miembros de la
comunidad cuando se están desplazando a través de
la ciudad.

“Ejemplo”: FON de Martin Varsavsky
• Modelo de negocio
– Bill: ofrece su ADSL por WiFi y es recompensado
– Alien: usa el WiFi y paga por el servicio
FON ≈ P2P + WiFi + cooperación
02/05/06
VIDEO: Anuncio de FON en la 2 de TVE
Redes cooperativas
Ejemplo: Fon
02/05/06
Redes cooperativas
Ejemplo: Fon
02/05/06
Redes cooperativas
Ejemlo: Guifi.net
• guifi.net és la suma de
molts nodes que aporten
connectivitat als usuaris.
Cada node dóna servei
als clients que estan a
prop seu i a la vegada
s’interconnecta amb
altres nodes propers per
crear una xarxa lliure,
gratuïta, alternativa i
d’alta velocitat.
02/05/06
Definición
A social network is a social structure made of nodes
which are generally individuals or organizations. It
indicates the ways in which they are connected through
various social familiarities ranging from casual
acquaintance to close familial bonds. The term was
first coined in 1954 by J. A. Barnes (in: Class and
Committees in a Norwegian Island Parish, "Human
Relations"). The maximum size of social networks
tends to be around 150 people (Dunbar's number) and
the average size around 124 (Hill and Dunbar, 2002).

Examples: LinkedIn, Tribe, openBC, Ryze, MeetUp,
eVite, MySpace
Redes sociales

02/05/06
El problema de los free riders

From Wikipedia, the free encyclopedia:
“In economics and political science free riders are actors
who consume more than their fair share of a resource, or
shoulder less than a fair share of the costs of its production.
The free rider problem is the question of how to prevent
free riding from taking place, or at least limit its negative
effects.”
02/05/06
El problema de los free riders
Free Riding on Gnutella by Eytan Adar and Bernando A. Huberman
02/05/06
Sobreexplotación de los recursos
(tragedy of commons)
Freeriding and tragedy of the commons are two
major problems Nearly 70% of Gnutella users do
not share any file with the P2P community and
nearly 50% of all search responses come from
the top 1% of content sharing nodes. Therefore,
nodes that share resources are always
congested and the tragedy of the commons
occurs. Freeriding and tragedy of the commons
are two major problems. Therefore, nodes that
share resources are always congested and the
tragedy of the commons occurs .
02/05/06
Políticas para detener/reducir estos problemas
One common approach has been to ignore rationality problems
and hope for the best.
One reason why these systems may work is that there can be
enough obedient users following a given protocol, even when it
might be rational not to do so.
Alternatively, existing systems may work because there are
enough rational users that maximize their expected utility by
the enjoyment of providing a common good. This altruistic
behavior is outside of typical game-theoretic models.
02/05/06
Incentive Mechanism
How to encourage cooperation among strangers?
Challenges: large, dynamic groups with anonymity,
hidden action, hidden information, and asymmetries
of interest.
02/05/06
Incentive Mechanism
•Tokens/currency
• Appropriate for trading of multiple resource types
• Examples: Mojonation, KARMA, tycoon, ...
•Barter/taxation
• Appropriate for single commodity type
• Sometimes called tit-for-tat or bit-for-bit
• Examples: BitTorrent, ESM
•Reciprocity
• Direct reciprocity (repetition)
• Indirect reciprocity (reputation)
02/05/06
Direct Reciprocity
Bob
Repetition encourages cooperation
e.g., Prisoner's Dilemma game:
• one-shot game: mutual defection is dominant
strategy infinitely
• repeated game: mutual cooperation is dominant
Simple tit-for-tat (TFT) strategy works very well in
iterated prisoners' dilemma (IPD) tournaments
Clustering (e.g., clubs) and server selection (e.g.,
CoopNet) may facilitate direct reciprocity
02/05/06
Alice
BitTorrent: Dilema del prisionero
02/05/06
Indirect Reciprocity
Bob
Carol
•Peers earn reputation via cooperation
•Reputable peers receive preferential treatment
•Implementation overhead for maintaining
reputation information
•Various proposals:
• Image scoring
• Free Haven
• Eigentrust
• Differentiated admission
• CONFIDANT
02/05/06
Alice
Mechanism design
The idea in mechanism design (MD) is to define the
strategic situation, or rules of the game, so that the
system as a whole exhibits good behavior in equilibrium
when self-interested nodes pursue self-interested
strategies.
Mechanism design can be thought of as inverse game
theory – where game theory reasons about how agents will
play a game, MD reasons about how to design games that
produce desired outcomes.
02/05/06
Mechanism Design
Design of protocols such that in equilibrium,
the outcome can be shown to exhibit certain properties.
Mapping from strategies (actions) of agents to payoffs.
Mapping from strategies
(actions) of agents to
payoffs.
02/05/06
Mapping from strategies
(actions) of agents to payoffs.
Price of Anarchy (Selfishness and how to cope with it)
How much does the society suffer by the lack of
coordination between players?
The optimal social utility function happens when
we have a single authority who dictates every agent what
to do. In contrast, when agents choose their own action,
we should study their behavior and compare the obtained
social utility with the optimal one.
02/05/06
Economy
Economics is the study of how societies use scarce
resources to produce valuable commodities and
distribute them among different people.
Samuelson, Nordhaus - 1998 – Economics, p. 4
02/05/06
Beyond Homo Economicus (rationality
revisited)
•Altruism
Information gift economies
e.g. linux, creative commons, wikipedia, ...
Warm-glow
"Digital Robin Hoods"
•Strong reciprocity
Reciprocate (reward cooperators and/or punish
defectors) even if action reduces own utility
Ultimatum, Dictator, and Public Goods games: 5060% of subjects exhibit reciprocal behavior, 20%
exhibit selfish behavior
Considerations of fairness and social norms
•Even selfish individuals may not be perfectly selfish
•bounded rationality or near rationality vs.
hyperrationality
•imperfect knowledge; imperfect execution (e.g.,
02/05/06trembling hand)
Assignment problem
Redes P2P


Resource allocation: the aggregate power of all
computers on the Internet is huge. In a “dream world"
this aggregate power will be optimally allocated online
among all connected processors. One could imagine
CPU-intensive jobs automatically migrating to CPUservers, caching automatically done by computers with
freedisk space, etc. Access to data, communication
lines, and even physical attachments (such as printers)
could all be allocated across the Internet. This is clearly
a dicult optimization problem even within tightly linked
systems, and is addressed, in various forms and with
varying degrees of success, by all distributed operating
systems.
The same type of allocation over the Internet requires
handling an additional problem: the resources belong
to different parties who may not allow others to freely
use them. The algorithms and protocols may, thus,
need to provide some motivation for these owners to
“play along".
Conclusiones



Redes + social es un tema de investigación vivo y que
engloba muchas disciplinas
Esperamos nuevas que en los próximos años aparezcan
nuevas killer applications que cambien nuestras vidas
(Skype, …)
Tecnologías que descentralizan pueden ayudar a
construir comunidades sociales
02/05/06
Referencias

P2P Working Group


Grid Forum P2P


https://forge.gridforum.org/projects/p2p
FreeNet


http://www.peer-to-peerwg.org
http://freenetproject.org
[email protected]

02/05/06
http://setiathome.ssl.berkeley.edu/
Referencias








"BitTorrent Economics Paper" , Bram Cohen
"BitTorrent protocol specification" , Bram Cohen
"BitTorrent Resource Availability Analysis" , Brian Greinke
and James Hsia. (Rice)
"Dissecting BitTorrent: Five Months in a Torrent's
Lifetime" , M. Izal, G. Urvoy-Keller, E.W. Biersack, P.A.
Felber, A. Al Hamra, and L. Garc es-Erice. (Institut
Eurecom, France)
“Pollution in P2P file Sharing Systems”
http://cis.poly.edu/~ross/papers/pollution.pdf
Rationality and Self-Interest in Peer to Peer Networks by
“Jeffrey Shneidman and David C. Parkes”
An Excess-Based Economic Model for Resource
“Allocation in Peer-to-Peer Networks” by Christian Grothoff
02/05/06
Referencias





“In Search of Homo Swappus : Evolution of Cooperation in
Peer-to-Peer Systems” by John Chuang
“The Past and Future of Multiagent Systems” by José M.
Vidal
“Structure in Articial Societies” by Josep Maria Pujol
Guifi.net: http://guifi.net/ca/book/print/371
“Reputation and Location Privacy in Cooperative Networks”
by Jonathan Bredin
02/05/06
Referencias





"Multiagent Systems“ by G.Weiss
"Multi-Agent Systems“ by J. Ferber
"Foundations of Distributed AI“ by G. M. P. O'Hare and N.
R. Jennings
"Readings in Agents“ by M. Singh and M. Huhns.
“An Introduction to Multiagent Systems” by Michael
Wooldridge
02/05/06
Questiones
?
Questions or more information:
[email protected]
02/05/06