Passage B Smart Objects and Related Technology

Smart objects represent the middle ground between computing and telephony,borrowing from both.From its computing heritage,smart objects have assumed the culture of engineering evolvable systems.This is important because at this point,it is impossible to fully specify the expected behavior of future smart object systems,even if we have a good idea of where smart objects are heading today.From its telephony heritage,smart objects have applied the principles from connecting disparate systems that may be managed by different companies and organizations.Smart objects are not manufactured by a single organization,but by multitudes of different people and parties.Smart object technology must be both evolvable and standardized.

We discuss today's smart objects as shown in Figure 1.2: embedded systems,ubiquitous and pervasive computing,mobile telephony,telemetry,wireless sensor networks,mobile computing,and computer networking.Some of these areas come from the computing heritage and some from the telephony heritage.Some have sprung out of academic research communities,some from an industrial background.What they have in common,however,is that they either deal with computationally assisted connectivity among physical items,wireless communication,or deal with interaction between the virtual and the physical world.

Ⅰ.Embedded Systems

An embedded system is a computer embedded in something other than a computer.Under this definition,any system that has a microprocessor is an embedded system with the exception of PCs,laptops,and other equipment readily identified as a computer.Thus this definition of an embedded system would include smart objects.Figure 1.3 illustrates different types of embedded systems.

The primary difference between a traditional embedded system and a smart object is that communication is typically not considered a central function for embedded systems,whereas communication is a defining characteristic for smart objects.Although there are many examples of communicating embedded systems,such as car engines with embedded microprocessors that can communicate their status information with a computer connected to the engine at service time,these systems are not defined by their ability to communicate.A car engine that cannot communicate can still operate as a car engine.In contrast,a smart object such as a wireless temperature sensor deprived of its communication abilities would no longer be able to fulfill its purpose.

Ⅱ.Ubiquitous and Pervasive Computing

Ubiquitous computing,also called pervasive computing,is a field of study based on the concept of what happens when computers move away from the desktop and become immersed in the surrounding environment.Ubiquitous computing,as a research discipline,originated in the mid-1980s.Mark Weiser,a professor at MIT,published two short notes titled “Ubiquitous computing #1” and “Ubiquitous computing #2.”,which described that computing would move into our daily environment,living in “the woodwork of everywhere” as exemplified in Figure 1.4.He criticized the trend of making computers exciting objects in their own right.He took a different perspective: instead of making computers the central object,they would become invisible.

Ubiquitous computing has become an established academic research field with several major annual conferences and a number of scientific journals.Hundreds of doctoral theses have been written about this topic over the last two decades.As an academic discipline,ubiquitous computing places a strong focus on building real systems that embody its ideas.There is a long string of important prototype systems that come from the ubiquitous computing community.These prototypes have been instrumental in pursuing the field of ubiquitous computing as well as demonstrating the feasibility of an ever-connected world.Wearable computing is a field that has grown out of the ubiquitous computing community.With wearable computing,the computing infrastructure moves onto the body of its users or into their clothing.Wearable computers make ubiquitous computing truly person-centric.

Smart objects owe much of their history to ubiquitous computing.Many of the early developments and vision in ubiquitous computing directly apply to smart objects.Whereas ubiquitous computing is interested in the interaction between ubiquitous computing systems and humans,the area of smart objects takes a more technical approach.Much of the technology developed for smart objects has a direct applicability to ubiquitous computing.Similarly,most of the designs that have been developed within the ubiquitous computing community can be applied to smart objects as well.

Ⅲ.Mobile Telephony

Mobile telephony grew out of the telephony industry with the promise of ubiquitous access to telephony.Today,mobile telephony not only provides telephony everywhere,but also Internet access.In the late 1990s,nearly 20% of the population in the developed world had a mobile telephone.In 2008,there were more than 4 billion mobile telephony subscribers.

Mobile telephony is often called cellular telephony,and mobile phones are called cell phones,because of the structure of the wireless networks in which mobile phones operate.The network is divided into cells where each phone is connected to exactly one cell at any given time.A cell covers a physical area whose size is determined by the network operator.Since each cell typically handles a limited number of simultaneous phone calls,network operators plan their networks so that cells are smaller and more numerous in areas where operators expect more people to make phone calls.Each cell is operated by a cell tower on which a wireless transceiver base station is mounted.The base station maintains a wireless connection to all active phones in its cell.When the user and the phone move to another cell,the base stations perform an exchange called a handover.

Mobile telephony has given rise to long-range wireless networking technology such as Global System for Mobile communications (GSM),General Packet Radio Service (GPRS),Enhanced Data Rates for GSM Evolution (EDGE),and Universal Mobile Telecommunications System (UMTS) as well as short-range wireless communication technology such as Bluetooth (IEEE 802.15.1).Long range communication is used to transmit voice and Internet data from the mobile phone to the nearest base station.Short-range wireless communication is used for communication between the phone and wireless accessories such as wireless headsets.

Mobile telephony has revolutionized the way we think of personal connectivity.Telephony used to be restricted to a few physical locations: we had a phone at the desk in our office and a few phones at strategic locations in our homes,such as the kitchen or next to the TV.As telephony became mobile,we stopped thinking about telephony as location-bound,but as a ubiquitous always-on service,available everywhere.Mobile telephony not only revolutionized person-to-person access,but changed the way we view network access.With modern smart phones,Internet access is no longer confined to PCs; it is truly ubiquitous.With a few quick button presses,e-mail,instant messaging,and the World Wide Web are immediately available.Instant Internet access is equally available in foreign countries,even if it sometimes costs a small fortune.

The way mobile telephony changed the general view on connectivity is an important factor for the continued development of smart objects.As we are now accustomed to thinking of connectivity as ubiquitous,we are equally accustomed to thinking of access to smart objects as ubiquitous.

Ⅳ.Telemetry and Machine-to-machine Communication

The word telemetry is a portmanteau of the Greek words tele (remote) and metron (to measure).Telemetry is,as the name implies,about performing remote measurements.Machine-to-machine communication is a generalization of telemetry that implies autonomic communication between nonhuman operated machines and is central to the concept of telemetry.Telemetry is used to transmit information about current temperature,humidity,and wind from distant weather stations (Figure 1.5).Telemetry is used to transmit fuel consumption data from trucks so that the owner can optimize the truck's routes to save on fuel costs,and as a consequence reduce pollution.

The concept of machine-to-machine communication and telemetry is also used in shorter distances.Today's pacemakers (devices that are implanted in the hearts of people who have had a heart attack) frequently include a device called a “telemetry coil.” This allows a doctor to monitor the pacemaker's activity without surgery.Instead,the doctor uses a device that creates a low-power electromagnetic field near the patient.The telemetry coil reacts to the electrical field by modulating it creating a low-power communication mechanism with which information can be transferred from the patient's heart to the doctor.

Telemetry and machine-to-machine communication are similar to smart objects because they are both used to perform large-scale measurements.With telemetry,these measurements can be performed from a remote site without direct physical access.Remote access using telemetry is most often performed with existing mobile telephony networks such as GSM or 3G (UMTS),or via dedicated networks such as the Inmarsat satellite network.Smart objects are not only used for measurements and sensing,but also affect their environment by using actuators.Nevertheless,much of the remote access technology developed for telemetry systems can be used with and applied to smart object systems.

Ⅴ.Wireless Sensor and Ubiquitous Sensor Networks

Wireless sensor networks have evolved from the idea that small wireless sensors can be used to collect information from the physical environment in a large number of situations ranging from wild fire tracking and animal observation to agriculture management and industrial monitoring.Each sensor wirelessly transmits information toward a base station.Sensors help each other to relay the information to the base station.The research field of wireless sensor networks has been very active since the early 2000s with several annual conferences,many journals,and a large number of annual workshops.Wireless sensor networks are sometimes called ubiquitous sensor networks to highlight the ubiquity of the sensors.

Early work in wireless sensor networks envisioned sensor networks to be composed of so-called smart dust.Smart dust would be composed of large numbers of tiny electronic systems with sensing,computation,and communication abilities.It would be spread over an area where a phenomenon,such as humidity or temperature,was to be measured.Because the dust specks would be so small,they could be dispersed using mechanisms such as air flow.The applications of smart dust would initially be used by the military to track the location of enemies,to signal an alarm when intruders were found,or to detect the presence of a vehicle.

The concept of smart dust was,however,too restrictive for most uses.The limited physical size of the dust specks severely limited possible communication mechanisms and the computational capability of the nodes.Instead,many research groups started building hardware prototypes with a larger physical size that were easier to use for experimentation.The research community around wireless sensor networks has developed many important mechanisms,algorithms,and abstractions.Wireless sensor networks are intended to have a long lifetime.Since wireless sensors typically use batteries,having a long lifetime to translate into reducing the power consumption of the individual nodes.Thus,several power-saving mechanisms have been designed,deployed,studied,and evaluated both in simulators and in actual deployments.Many of these have a direct applicability to smart objects.

Wireless sensor networks have further spurred work in standardization for industrial automation and monitoring.Many of the recent standards in wireless industrial networking,such as Wireless HART and ISA100a,have their roots in the wireless sensor networking community.

The concept of wireless sensor networks is similar to that of smart objects,and much of the development in smart objects has occurred in the community around wireless sensor networks.Wireless sensor networks are composed of small nodes,equipped with a wireless communication device,that autonomously configure themselves into networks through which sensor readings can be transported.Smart object networks are less focused on pure data gathering,but are intended for a large number of other tasks including actuation and control.Furthermore,wireless sensor networks are primarily intended to be operated over a wireless radio communications device.In contrast,the concept of smart objects is not tied to any particular communication mechanism,but can run over wired as well as wireless networks.

Ⅵ.Mobile Computing

Mobile computing is the field of wireless communication and carry-around computers,such as laptop computers.In some ways the mobile computing field spun out of work initialized within the ubiquitous computing area.Likewise,the early focus on wireless networking led to wireless communication mechanism research.Work on these mechanisms began in the mid-1980s and led up to the standards around wireless local area networks (Wi-Fi) that started forming in the late 1990s.Today,so-called Wi-Fi hot spots at public places such as coffee houses,libraries,and airports are common.Users may connect to the Internet through this wireless network either gratis or for a fee.

In academia,the field of mobile computing also carried over into the research field of Mobile Adhoc NETworks (MANETs).MANET research focuses on networking mechanisms for wireless computers where no network infrastructure exists.In such situations,routing protocols and other network mechanisms must quickly establish an ad hoc network.The network formation is made in a distributed manner where each node that participates in the network must take part in the network's mechanisms such as routing and access control.The MANET community has developed several important routing protocols for these networks such as the standardized AODV and DSR protocols.

Just as with mobile telephony,the use of mobile computing has permeated the understanding that network access is ubiquitous.As Wi-Fi access has become widespread,we now take connectivity for granted anywhere,instantly.

Ⅶ.Computer Networking

Computer networking is about connecting computers to allow them to communicate with each other.Computers are connected using networks as shown in Figure 1.6.These networks were initially wired,but with the advent of mobile computing,wireless networks are available.

The field of computer networking is significantly older than that of mobile computing.Computer networking began in the early 1960s when the breakthrough concepts of packet-switched networking were first described by Leonard Kleinrock at UCLA.Earlier telephony networks were circuit-switched,and each connection (phone call) created a circuit through the network where all data were transported.With packet-switched networking,no circuits were constructed through the network.Instead,each message was transported as a packet through the network where each node would switch the packet depending on its destination address.

After Kleinrock's breakthrough,ARPANET was created as the first large-scale computer network built on the concepts of a packet-switched network.During the late 1970s and early 1980s,ARPANET was gradually replaced with the early versions of the Internet.ARPANET started to use the IP protocol suite in 1983 before becoming the Internet.

The ARPANET and the Internet were built on a powerful concept called the end-to-end principle of system design,named by an influential paper by Jerome H.Saltzer,David P.Reed,and David D.Clark.The end-to-end principle states that functionality in a system should be placed as long as possible toward the end points.This principle has arguably been one of the most important aspects of the design of the Internet system,because it allowed the system to gracefully support an ever-growing flora of applications from simple e-mail and file transport of the 1980s through the Web revolution of the 1990s transmission to high-speed,real-time video,and audio transmissions of the 2000s.The connection between computer networking and smart objects is evident: communication is one of the defining characteristics of smart objects.

Ⅷ.New Words

heritage['herɪtɪdʒ]　　　　　　　n.遗产；传统；继承物；继承权

manufactured[mænjə'fæktʃɚd]　　 adj.制造的，已制成的

ubiquitous[juː'bɪkwɪtəs]　　　　　adj.泛在的；无所不在的

pervasive[pə'veɪsɪv]　　　　　　 adj.普遍的；到处渗透的

realtime　　　　　　　　　　 adj.实时的；适时的

synonymous[sɪ'nɒnɪməs]　　　　 adj.同义的；同义词的；等同于……的

rudder['rʌdə]　　　　　　　　 n.船舵；飞机方向舵

Ⅸ.Abbreviations

RTOS　Realtime Operating Systems　　　　　　　　 实时操作系统

GSM　Global System for Mobile communications　　　 全球移动通信系统

GPRS　General Packet Radio Service　　　　　　　　通用分组无线服务技术

EDGE　Enhanced Data Rates for GSM Evolution GSM　 演进的增强数据率

UMTS　Universal Mobile Telecommunications System　 通用移动通信系统

IEEE　Institute of Electrical and Electronics Engineers　　电气和电子工程师协会

MANETs　Mobile AdhocNETworks　　　　　　　　 移动自组织网络