sensor networks and ambiente intelligence

Redes de Sensores em AmbientesInteligentes, ISMAI, 2013

F. Luís Neves <[email protected]>

Rui M. Barreira <[email protected]>

Program

1. Context and Application

2. Wireless Sensor Networks

(WSNs)

3. Ambient Intelligence in

Practice

4. Topologies and Protocols.

5. Development Platforms

6. Embedded and

Ubiquitous Computing

7. Context Awareness

8. Projecting Applications

supported by WSNs

1.Context and Applications

1. Ambient Intelligence

2. Core Problems and Challenges

3. Key Technological Areas

4. The User as the Center of the

System


The most profound technologies are those

that disappear. They weave themselves into

the fabric of everyday life until they are

indistinguishable from it.

The Computer for the 21st Century, by Mark

Weiser, 1991

A vision for our environment

Smart electronic environments that are

sensitive and responsive to the presence of

people;

Electronics embedded in every-day objects;

natural interaction; context aware;

personalized; adaptive; responsive; pro-active;

Enhancing productivity, healthcare, well-being,

expressiveness, creativity;

Intelligent user friendly interfaces.


Ubiquidade (ou omnipresença), ou seja, situações em que estamos

rodeados de conjuntos multifacetados de sistemas embebidos;

Precaução, ou seja, a capacidade para localizar e reconhecer objectos,

pessoas e intenções;

Inteligência, ou seja, capacidade de analizar o contexto, adaptar-se a esse

contexto e às pessoas que nele interagem, capacidade de “aprendizagem”

através do comportamento e do reconhecimento de emoções e da

interacção natural;

Utilização de meios de comunicação “naturais”, tais como a

reconhecimento linguístico e a consequente utilização da linguagem natural.

PrincipaisConceitos


Ambientes inteligentes

Ambientes cooperativos

Edifícios inteligentes

Casas inteligentes

Redes móveis

Computação móvel

Interacção natural

“Os homens viverão em breve rodeados de ambientes

inteligentes através de interfaces inteligentes suportadas

por computadores em rede embebidos no nosso dia a dia

habitacional.”

Programa Europeu IST – Information Society Technologies

Pervasive computing (no sentido da presença tecnológica invasiva)

Ubiquitous computing (no sentido da omnipresença tecnológica)

Wearable computing (no sentido da “vestimenta” tecnológica)


• Qual o impacto social derivado da utilizado de

sistemas de AmI?

• Qual o seu verdadeiro potencial na melhoria da

qualidade de vida?

• Como se conjugam nestes ambientes os aspectos

relacionados com a privacidade e a confiança?

• Que características podemos encontrar nas diferentes

interacções possibilitadas pelos sistemas AmI?

Questões


• Qual o nível de inteligência que as

pessoas estão dispostas a aceitar?

• Como definir as diferentes dimensões do

termo “ambiente”?

• Como fazer refletir o design nos espaços

interactivos e nos artefactos inteligentes?

• Como fazer reflectir a utilização diária de

aparelhos na interacção implicita?

Questões






System


… it is not technological…

Understanding the functioning of the physical, natural,

biological, cultural, technical social reality that we live in.

2. Core Problems and ChallengesInterdisciplinary Ambient Intelligence

Architecture

Design

Sociology

Anthropology

Cognitive Science

Neuroscience

Psychology

Engineering

Ambient Intelligence

Intelligent Interfaces

Ubiquitous Communications


2. Core Problems and Challenges Ambient Intelligence started as…

Technology Integrator

2. Core Problems and Challenges What we have and what we need…

What we Have

What we Need

Integration

Scalable and Robust Solutions

Business Models

Standards and Lead Markets

Building blocks

Shared scenarios

Interdisciplinary awareness

New practices of research and innovation

2. Core Problems and Challenges Criticism and Social Impact

Social, Political and Cultural concerns about:

The loss of consumer privacy

Fear for an increasingly individualized,

fragmented society

Hyper real environments where the virtual is indistinguishable from the real

Welcome to a world through Glass

http://www.google.com/glass/start/what-it-does

2. Core Problems and Challenges Social and Political aspects

Should facilitate human contact;

Should be orientated towards community and cultural enhancement;

Should help to build knowledge and skills for work, better quality of work, citizenship and consumer choice;

Should inspire trust and confidence;

Should be consistent with long term sustainability - personal, societal and environmental - and with life-long learning;

Should be made easy to live with and controllable by ordinary people.

2. Core Problems and Challenges Emblematic Projects

Philips Homelabs


Mit Media Lab


Home of the Future

Bill and Melinda Gates' $97 million house

Home automation is defined as a process or system which provides the ability to enhance one's lifestyle, and make a home more comfortable, safe and efficient.

Home automation can link lighting, entertainment, security, telecommunications,office automation, heating and air conditioning into one centrally controlled system.

2. Core Problems and Challenges Market Trends






System

3. Key Technological AreasAmbient Intelligence Building Blocks

Ambient Intelligence


Pervasive Computing

Wearable Computing

Mobile Computing

Embedded Systems

Personalized Systems

Context Awareness

Adaptive Systems

Intelligent Agents

Human-Centric UIs






System

The User as the Center of the SystemWhat is Usability?

Jakob Nielsen

Usability is the measure of thequality of the user experience wheninteracting with something -whether a website, a traditionalsoftware application, or any otherdevice the user can operate insome way or another.

The User as the Center of the SystemWhat is Usability?

ISO 9421

Usability is a measure of theeffectiveness, efficiency andsatisfaction with which specifiedusers can achieve specified goals ina particular environment.

The User as the Center of the SystemPutting People First

How to make informed (proactive) choices about sharing information?

How to learn how other people protect their information?

How to share information with an intended audience?(e.g. friends, my family and their friends)

Much more than usability – What is the framework for social communication?


Communication

Processes

• Social navigation

• Legitimate peripheral participation

• Social translucence

Structures

• Relationships

• Social networks


Support “peace of mind”Augment common household object

Maintain awareness over distance

2.Wireless Sensor Networks (WSN)

1. Origins

2. Hardware Platforms

3. Operating Systems

4. Networking

5. Security

6. Applications

7. Standardization

Wireless Sensor NetworksOrigins

1958: Advanced Research Projects Agency (ARPA)

created by president Dwight D. Eisenhower.

1972: ARPA renamed to "DARPA" (for Defense)

1978: Technology components for a DSN were

identified (Proceedings of the Distributed Sensor

Nets Workshop, 1978):

• sensors (acoustic)

• communication and processing modules, and

• distributed software

1980: The origins of the research on WSNs

can be traced back to the Distributed

Sensor Networks (DSN) program at the

DARPA

DSNs were assumed to have many spatially

distributed low-cost sensing nodes that

collaborated with each other but

operated autonomously, with information

being routed to whichever node was best

able to use the information.


Initial Limitations:

• Size: sensors were rather large (i.e. shoe

box and up) which limited the number of

potential applications.

• Price: the earliest DSNs were not tightly

associated with wireless connectivity.

1988: New wave of research in WSNs mainly

focused on networking techniques and

networked information processing suitable

for highly dynamic ad hoc environments.

1990s: Appearance of sensor nodes:

• much smaller in size

• much cheaper in price

Many new civilian applications of sensor networks

such as environment monitoring, vehicular sensor

network and body sensor network have emerged.

2001: SensIT (Kumar & Shepherd) provided the

present sensor networks with new capabilities

such as ad hoc networking, dynamic querying

and tasking, reprogramming and multitasking.


2003: Institute of Electrical and Electronics

Engineers (IEEE) has defined the IEEE

802.15.4 standard which specifies the

physical layer and media access control for

low-rate wireless personal area networks.

2003: Based on IEEE 802.15.4, ZigBee

Alliance has published the ZigBee standard

which specifies a suite of high level

communication protocols which can be

used by WSNs.

Currently, WSN has been viewed as one of

the most important technologies for the

21st century (21 Ideas for the 21st Century,

1999).

Countries such as China have involved

WSNs in their national strategic research

programmes.

The commercialization of WSNs are also

being accelerated by new formed

companies.


1. Origins

2. Hardware Platform


4. Networking

5. Security

6. Applications

7. Standardization

Wireless Sensor NetworksHardware Platform

Network: A WSN consists of spatially

distributed sensor nodes.

Each sensor node is able to independently

perform some processing and sensing

tasks.

Sensor nodes communicate with each

other in order to forward their sensed

information to a central processing unit or

conduct some local coordination such as

data fusion.


Sensor nodes: micro-electronic devices powered

by a limited power source. Because of that, the

attached sensors should also be small in size and

consume extremely low energy.

A sensor node can have one or several types of

sensors integrated in or connected to the node.

Memories in a sensor node include in-chip flash

memory and RAM of a microcontroller and

external flash memory.

A sensor is a hardware device that produces a

measurable response signal to a change in a

physical condition (e.g. temperature, pressure,

humidity). Sensor Node (typical) Architecture


Embedded Processor: the functionality of

an embedded processor is to schedule

tasks, process data and control the

functionality of other hardware components.

The Microcontroller has been the most

used embedded processor for sensor

nodes because of its flexibility to connect to

other devices and its cheap price.

Types of embedded processors that can be used in a sensor node:

• Microcontroller, a small computer on a single integrated circuit

containing a processor core, memory, and programmable I/O

peripherals

• Digital Signal Processor (DSP), a specialized microprocessor with an

architecture optimized for the operational needs of digital signal

processing (measure, filter and/or compress continuous real-world

analog signals)

• Field Programmable Gate Array (FPGA), an integrated circuit designed

to be configured by a customer or a designer after manufacturing and

which contains programmable logic components called "logic blocks"

• Application Specific Integrated Circuit (ASIC), an integrated circuit

(IC) customized for a particular use, rather than intended for general-

purpose use


Transceiver: A transceiver is responsible for

the wireless communication of a sensor node.

The various choices of wireless transmission

media include:

• Radio Frequency (RF)

• Laser and

• Infrared.

RF based communication fits to most of

WSN applications.

The operational states of a transceiver are:

• Transmit

• Receive

• Idle and

• Sleep.

ZigBee ZM-24 Transceiver Module, from RTI Corp.


Power Source: In a sensor node, power is

consumed by sensing, communication and

data processing.

More energy is required for data

communication than for sensing and data

processing.

Power can be stored in batteries or

capacitors.

Batteries are the main source of power

supply for sensor nodes.


1. Origins



4. Networking

5. Security

6. Applications

7. Standardization

Wireless Sensor NetworksOperating Systems

The role of any operating system (OS) is

to promote the development of reliable

application software by providing a

convenient and safe abstraction of hardware

resources.

OSs for WSN nodes are typically less

complex than general-purpose OSs both

because of the special requirements of WSN

applications and because of the resource

constraints in WSN hardware platforms.

TinyOS is an operating system specifically

designed for WSNs.

It features a component-based

architecture which enables rapid innovation

and implementation while minimizing code

size as required by the severe memory

constraints inherent in WSNs.

TinyOS’s component library includes

network protocols, distributed services,

sensor drivers, and data acquisition tools

Wireless Sensor NetworksOperating Systems

Contiki is another open source OS specifically

designed for WSNs.

The Contiki kernel is event-driven, like

TinyOS, but the system supports

multithreading on a per application basis.

Furthermore, Contiki includes protothreads

(lightweight threads) that provide a thread-like

programming abstraction but with a very small

memory overhead.

Contiki provides IP communication, both for

IPv4 and IPv6.


1. Origins



4. Networking

5. Security

6. Applications

7. Standardization

Wireless Sensor NetworksNetworking

A WSN is a network consisting of numerous

sensor nodes with sensing, wireless

communications and computing capabilities.

These sensor nodes are scattered in an

unattended environment (i.e. sensing field) to

sense the physical world.

The sensed data can be collected by a few sink

nodes which have accesses to infrastructured

networks like the Internet.

Finally, an end user can remotely fetch the

sensed data by accessing infrastructured

networks.

Wireless Sensor NetworksNetworking: Network Architecture

The protocol stack is an implementation of a

computer networking protocol suite.

The suite is the definition of the protocols,

and the stack is the software

implementation of them.

Protocol Layer

HTTP Application

TCP Transport

IP Internet/Network

Ethernet Data Link/Link

IEEE 802.3u Physical

Protocol Stack is a set of network protocol

layers that work together.

The term stack also refers to the actual

software that processes the protocols

Wireless Sensor NetworksNetworking: Protocol Stack of WSNs

The sensor network protocol stack is much like the

traditional protocol stack, with the following layers:

• Application

• Transport

• Network

• Data link and

• physical.

The physical layer is responsible for frequency

selection, carrier frequency generation, signal

detection, modulation and data encryption.

The data link layer is responsible for the multiplexing of data

streams, data frame detection, medium access and error control.

It ensures reliable point-to-point and point-to-multipoint

connections in a communication network.

The network layer takes care of routing the data supplied by

the transport layer. The network layer design in WSNs must

consider the power efficiency, data-centric communication, data

aggregation, etc.

The transportation layer helps to maintain the data flow and

may be important if WSNs are planned to be accessed through

the Internet or other external networks.

Depending on the sensing tasks, different types of application

software can be set up and used on the application layer.


WSNs must also be aware of the following

management planes in order to function

efficiently:

• Mobility

• Power

• Task

• Quality of Service (QoS) and

• Security management planes.

The mobility management plane detects and

registers movement of nodes so a data route to

the sink is always maintained.

The power management plane is responsible

for minimizing power consumption and may

turn off functionality in order to preserve energy.

The task management plane balances and

schedules the sensing tasks assigned to the

sensing field and thus only the necessary nodes

are assigned with sensing tasks and the remainder

are able to focus on routing and data aggregation.


QoS management in WSNs can be very

important if there is a real-time requirement

with regard to the data services.

QoS management also deals with fault

tolerance, error control and performance

optimization in terms of certain QoS

metrics.

Security management is the process of

managing, monitoring, and controlling

the security related behavior of a

network.

The primary function of security

management is in controlling access

points to critical or sensitive data.

Security management also includes the

seamless integration of different security

function modules, including encryption,

authentication and intrusion detection.

It is obvious that networking protocols

developed for WSNs must address all five of

these management planes.


1. Origins



4. Networking

5. Security

6. Applications

7. Standardization

Wireless Sensor NetworksSecurity

While the future of WSNs is very

prospective, WSNs will not be successfully

deployed if security, dependability and

privacy issues are not addressed

adequately.

These issues become more important

because WSNs are usually used for very

critical applications.

Security Threats in WSNs: A typical WSN

consists of hundreds or even thousands of tiny

and resource-constrained sensor nodes.

In a basic WSN scenario, resource constraint,

wireless communication, security-sensitive data,

uncontrollable environment, and even

distributed deployment are all vulnerabilities.

These vulnerabilities make WSNs suffer from an

amazing number of security threats.

WSNs can only be used in the critical applications

after the potential security threats are eliminated.

Wireless Sensor NetworksSecurity

Physical Layer Threats: there are more

threats to WSNs in the physical layer, due to

the non-tamper-resistant WSN nodes and

the broadcasting nature of wireless

transmission.

Link Layer Threats: The data link layer is

responsible for the multiplexing of data

streams, data frame detection, medium

access, and error control.

Network Layer Threats: Threats in the network layer

mostly aim at disturbing data-centric and energy

efficient multihop routing, which is the main design

principle in WSNs.

Application Layer Threats: Many WSNs’ applications

heavily rely on coordinated services such as

localization, time synchronization, and in-network

data processing to collaboratively process data.

Unfortunately, these services represent unique

vulnerabilities (e.g. False data filtering; Clock un-

synchronization)

Wireless Sensor NetworksSecurity Countermeasures

Generally, countermeasures to the threats in WSNs

should fulfill the following security requirements:

• Availability, which ensures that the desired

network services are available whenever required.

• Authentication, which ensures that the

communication from one node to another node is

genuine.

• Confidentiality, which provides the privacy of the

wireless communication channels.

• Integrity, which ensures that the message or the

entity under consideration is not altered.

• Non-reputation, which prevents malicious

nodes to hide or deny their activities.

• Freshness, which implies that the data is

recent and ensures that no adversary can

replay old messages.

• Survivability, which ensures the acceptable

level of network services even in the

presence of node failures and malicious

attacks.

• Self-security, countermeasures may

introduce additional hardware and software

infrastructures


The typical countermeasures to the threats in

WSNs are the following:

• Key Management: When setting up a

sensor network, one of the first security

requirements is to establish cryptographic

keys for later secure communication. The

established keys should be resilient to

attacks and flexible to dynamic update.

• Authentication: the authentication of the

data source as well as the data are critical

concerns.

• Proper authentication mechanisms:

can provide WSNs with both sensor and

user identification ability, can protect the

integrity and freshness of critical data,

and can prohibit and identify

impersonating attack.

• Intrusion Detection: Security

technologies, such as authentication and

cryptography, can enhance the security

of sensor networks.


Privacy Protection: As WSN applications

expand to include increasingly sensitive

measurements in both military tasks and

everyday life, privacy protection becomes an

increasingly important concern.

For example, few people may enjoy the

benefits of a body area WSN, if they know

that their personal data such as heart rate,

blood pressure, etc., are regularly

transmitted without proper privacy

protection.


1. Origins



4. Networking

5. Security

6. Applications

7. Standardization

Wireless Sensor NetworksApplications

Military sensor networks, which includes:

• large-scale acoustic ocean surveillance

systems for the detection of submarines

• self-organized and randomly deployed

WSNs for battlefield surveillance

• attaching microsensors to weapons for

stockpile surveillance

Environmental Monitoring, which includes:

• animal tracking

• forest surveillance

• flood detection

• weather forecasting.

It is a natural candidate for applying WSNs

because the variables to be monitored are

usually distributed over a large region (e.g.

temperature).


Health Monitoring, which includes special kinds of

sensors which can measure, for instance:

• blood pressure

• body temperature

• electrocardiograph (ECG)

These sensors can even be knitted into clothes to

provide remote nursing for the elderly.

When the sensors are worn or implanted for healthcare

purposes, they form a special kind of sensor network

called a body sensor network (BSN).

Traffic Control, which includes, for instance,

the massive installation of cheap sensor

nodes:

• in the vehicles

• at the parking lots

• along the roadside

• etc.


Industrial Sensing, which typically includes the

possibility to monitor the “health” of machines and

to ensure safe operation.

For example, a network of wireless corrosion

sensors can be economically deployed to reliably

identify issues (e.g. aging pipelines and tanks in the

oil and gas industry) before they become

catastrophic failures.

WSNs have also been suggested for use in the food

industry to prevent the incidents of

contaminating the food supply chain. (e.g. using

temperature sensors to check refrigerated transport).

Infrastructure Security, which includes the

use of WSNs for infrastructure security and

counterterrorism applications.

Critical buildings and facilities such as power

plants, airports, and military bases have to

be protected from potential invasions.

Networks of video, acoustic, and other

sensors can be deployed around these

facilities.


1. Origins



4. Networking

5. Security

6. Applications

7. Standardization

Wireless Sensor NetworksStandardization

The major standardization organizations are:

• the Institute of Electrical and Electronics

Engineers (IEEE)

• the Internet Engineering Task Force (IETF)

• the International Society for Automation

(ISA) and the HART Communication

Foundation,

IEEE 802.15.4 is a standard which specifies

the physical layer and MAC layer for low-

rate wireless personal area networks.

It is the basis for the ZigBee and

WirelessHART specification, each of which

further attempts to offer a complete

networking solution by developing the

upper layers which are not covered by the

standard.


ZigBee is a standard for a suite of high level

communication protocols based on the IEEE

802.15.4 standard for low power and low

data rate radio communications. Zigbee is

initiated and maintained by the Zigbee

Alliance - a large consortium of industry

players.

The typical application areas of Zigbee include:

• Smart energy monitoring

• Health care monitoring

• Remote control

• Building automation

• Home automation,

• etc.


WirelessHART is an open-standard wireless mesh

network (WMN) communications protocol designed

to meet the needs for process automation

applications.

The protocol utilizes IEEE 802.15.4 compatible

DSSS radios and it is operating in the 2.4GHz ISM

radio band.

On the data link layer, the protocol uses TDMA

(Time Division Multiple Access, a channel access

method for shared medium network) technology

to arbitrate and coordinate communications

between devices.

3.Ambient Intelligence in Practice

1. Home Security

2. Home Surveillance

3. Energy Monitoring

4. Appliances Control

5. Health Monitoring

Ambient Intelligence in PracticeHome Services

4.Topologies and Protocols.

1. Topologies

2. Protocols

3. Sensors

4. Actuators

5. Coordinators

5.Development Platforms

1. Ember

2. Contiki

6.Embedded, Ubiquitous and Wearable Computing

1. Embedded Computing

2. Ubiquitous Computing

3. Wearable Computing

3. Key Technological AreasEmbedded Computing: What is it?

Digital electronic system as well as other elements;

Application specific, not highly user programmable;

Digital logic interacts with the physical world.

3. Key Technological AreasEmbedded Computing: Attributes

Sensing and control;

Real-time operation;

Designed to meet multiple constraints;

Reliable;

Distributed;

Autonomous.

3. Key Technological AreasEmbedded Computing: Examples

Sensor networks;

Fly-by-wire;

Engine control;

Medical implants;

Space control.

3. Key Technological AreasEmbedded Computing: Applications

Improved quality of life: health care, homeland security, transportation, productivity, entertainment, etc;

Military applications: smart soldier, battlefield of the future, etc;

Because embedded computers are everywhere, large numbers are practitioners are needed;

Growing field needs new and improved techniques, architectures, etc;

3. Key Technological AreasWearable Computing: What is it?

•Controlled by the user;•Has both operational and interactional constancy, i.e. is always on and always accessible.

A computer that is subsumed into the personal space of the user

•Is always with the user;•Into which the user can always enter a command or receive relevant information, while walking around or doing other activities.

It is a device that:

3. Key Technological AreasWearable Computing: Attributes

Un monopolizing of the user’s attention: User can attend to other events;

Unrestrictive to the user: Allows interaction while user carries out normal functions;

Observable by the user: User can identify computational and non-computational components of their clothing;

Controllable by the user: User can take control at any time;

3. Key Technological AreasWearable Computing: Attributes

Attentive to the environment: Can enhance the user’s environment and situational awareness;

Communicative to others: Can be used as a communications medium;

Shares the same physical and situational context as the user.

3. Key Technological AreasWearable Computing: Military Applications

Onboard physiological/medical sensor suite to accelerate casualty care;

Netted communications to maximize robustness and integration of small teams;

Embedded training;

Enhanced situational awareness;

Synchronized firing of weapons from team.

3. Key Technological AreasUbiquitous Computing: What is it?

Interlacing and embedding computers into the environment and everyday items to streamline and simplify life;

Sensors support and interact with the environment;

Enables anytime, any place data access and manipulation;

Creates a self regulating and quasi-intelligent user interface.

3. Key Technological AreasUbiquitous Computing: Example

3. Key Technological AreasUbiquitous Computing: Challenges

• Elephant in the room: A central network hub necessary for the coordination of interlaced systems and sensors.

Handling mobility

• Coordination between sensors eliminates unnecessary power usage (leaving the light on or TV running)

Power supply for embedded sensors

• Where and how to structure interaction between man and machine

User Interface

3. Key Technological AreasUbiquitous Computing: In the Movies

• “Smart Car”

Knight Rider

• The doors have emotion, and express this when people used them

The Hitchhiker's Guide to the Galaxy

• Smart Paper

Minority Report

7.Context Awareness

1. Ember

2. …

3. Key Technological AreasContext Awareness: Definitions

• Several definitions of context in the literature;

• Any information that can be used to characterize a person, a placeor an object;

• It’s the “Who”, “Where”, “When” and “What” and determines the“Why”.

Context

• Several definitions of context in the literature;

• A system is context-aware if it uses the context information toprovide relevant information/services to the user, when itrelevancy depends on the user actions.

Context-awareness


• Direct Sensor Access.

• Middleware Infrastructure.

• Context Server.

Context acquisition architecture

• Widgets.

• Network Services.

• Blackboard Model.

Context Management


• Physical and virtual Sensors;

• Logic Sensors.

Sensor Infrastructure

• Key-Value Models;

• Markup Scheme Models;

• Graphical Models;

• Object Oriented Models;

• Logic Based Models;

• Ontology Based Models.

Context Modeling

References

1. Wireless Sensor Networks - An Introduction, Wireless Sensor Networks: Application-Centric Design, Yen Kheng

Tan (Ed.), ISBN: 978-953-307-321-7, InTech, Available from: http://www.intechopen.com/books/wireless-sensor-

networks-application-centric-design/wireless-sensornetworks-an-introduction

2. Sensor Networks: Evolution, Opportunities, and Challenges. Chee-Yee Chong, Member IEEE, and Srikanta P.

Kumar, Senior Member, IEEE. Proceedings of the IEEE, Vol. 91, No. 9, August 2003.

3. The Computer for the 21st Century, by Mark Weiser, 1991.

4. 21 Ideas for the 21st Century, 1999. BusinessWeek, August 30, 1999.