Embedded, Everywhere A Research Agenda for Networked Systems of Embedded Computers (2001) / Chapter Skim
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1. Introduction and Overview
1. Introduction and Overview
Pages 14-38
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From page 14... ...
The range of applications continues to expand with continued research and development. Aircraft manufacturers are already examining the possibility of incorporating processing devices into the wings of aircraft to allow fine-grained control of airflow and, hence, lift and drag; health researchers are investigating microscopic sensors that could traverse the bloodstream, monitoring health conditions and reporting them wirelessly; consumer electronics and information technology companies envision homes filled with intelligent devices that can interact with each other, homeowners, and appliance manufacturers to improve the quality of daily life.
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From page 15... ...
As computing has migrated from mainframe computers to minicomputers, personal computers, laptops, and, most recently, palmtop computers and information appliances, it has become more widespread and more a part of everyday life for millions. Meanwhile, embedded computers have been used in automobiles, aerospace engineering, and military applications for quite some time.
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In addition, EmNets present new opportunities for pervasive, transparent monitoring and information aggregation while at the same time generating a host of privacy and other ethical concerns. This report identifies and examines research challenges posed by EmNets and provides guidance for addressing them.
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Example 1: Automotive Telematics It should come as no surprise that the modern automobile is already a rolling network of embedded computers. In model year 2001, cars have between 20 and 80 microprocessors controlling everything from the running of the engine to the brake system to the deployment of the airbags.
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From page 18... ...
Many automobile manufacturers want to move away from the current model of diagnostics to a model of prognostics, which allows them to monitor their products for upcoming faults and allow those faults to be corrected before they happen. For this to be possible, there needs to be a way for the information gathered by the safety-critical parts of the automobile to be sent to the automobile manufacturer.
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From page 19... ...
One approach to this is General Motors' immensely successful OnStar offering.2 OnStar connects the car to the manufacturer, allowing the latter to monitor emergency situations and give on-demand help to the occupants of the car. Not only has this service provided GM with a market differentiator, it has also allowed the company to begin to provide a very profitable subscription service, giving it a revenue stream that is less prone to the fluctuations traditional in the automotive market.
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Information gathered by sensor networks in a field could be used to 4For more information on precision agriculture, see BANR (1998~. 5see Li and Wang `2000' for a description of a wireless sensor network for precision agriculture.
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These systems are moderately engineered (along a spectrum from highly engineered to ad hoc) , but the need to work under a wide range of unpredictable environmental conditions, as well as to interact with farm vehicles and new elements of the system as they become available, argues for adaptability within the EmNets at multiple time scales.
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In addition to battlespace shaping and force protection, EmNets will also be used for asset management. Defense forces rely on diverse vehicles, weapons, and equipment that require a mission-critical, high level of availability.7 EmNets enable distributed, condition-based monitoring for detecting wear and faults in vehicle chassis systems and vehicle power trains.
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From page 23... ...
Challenges include the need for security and low-power operation and the support of multiple biomedical sensor channels. Ultimately, the combination of EmNets for surveillance, condition monitoring, and personnel health status will enable a new tasking, control, and safety capability accessible at multiple command levels.
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The individual computing elements help to monitor and control the local system, acquiring information from a variety of sensors, implementing changes through a variety of actuators, making decisions locally, and/ or possibly relaying processed information to decision makers. · Natural or engineered contexts.
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, as well as those that exist where heat dissipation is a negative factor. Small form factor implies a fundamental limit on battery size, which in turn sets a fundamental limit on the number of bits that can be processed and/or communicated by the device during its entire lifetime.
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control over the overall system configuration, such as in sensor networks deployed in battlefield situations or in public smart spaces.8 New elements can be introduced into such systems by a number of actors/ participants, and the systems will automatically reconfigure. Such systems can be expected to have a high degree of heterogeneity in the computing elements they contain and a dynamic structure as elements enter and leave the network.
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EmNets Are Tightly Coupled to the Physical World As noted previously, a major distinguishing characteristic of EmNets is that they interact strongly with the physical world. One EmNet might control all of the major systems of a large battle cruiser.
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This factor places important constraints on the EmNet nodes, organization, system policies, and hardware. Untethered and/or mobile computing elements are usually battery operated, or perhaps they are very low power and run from solar panels.
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lust as it has taken many years to upgrade the basic telephone wiring systems to homes, despite growing demand for bandwidth, EmNets deployed in buildings, on farms, or in the countryside will face this same problem. The longevity of EmNets will thus have to be taken into account during design, as the basic technology will continue to evolve and the previously deployed system will eventually have to interoperate with the new technologies.
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From page 30... ...
It is easy to imagine deploying sensor technology with which one could sense various conditions within buildings or the environment; such networks might embody thousands or tens of thousands of nodes. In fact, building control systems with tens of thousands of nodes already exist.l° Networking many of these systems would yield systems of millions of nodes.ll Economics will allow such large systems to be built, and demand will come from many sources, ranging from environmental researchers to government regulators to the general public.
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From page 31... ...
An additional complicating factor is that people will less often interact with EmNets per se than with the devices and objects within which EmNet components are embedded. People's expectations of objects in their environment are likely to be very different from their expectations of explicitly computational or communication devices such as PCs or cell phones.
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From page 32... ...
These research areas involve system-level issues that arise from the interconnection of large numbers of long-lived information processing devices managed by users who are likely to be experts in a particular application domain but not necessarily in EmNet technology. These users will need to know not just whether the system is working or has failed, they also need to know how close to its safety margins or how healthy the system is so they can make intelligent decisions on whether to use it or take it offline and repair it.
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From page 33... ...
While EmNets have many characteristics that distinguish them from traditional systems, it is very likely that the techniques developed to realize EmNets will have enormous positive impact on the design of traditional systems as well; a key example is techniques for self-configuration (see Chapter 3~. It is important to note that networked systems of embedded computers will be and are being implemented, even without the benefit of additional research.
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From page 34... ...
Advances in MEMS technology have already made it feasible to sense odors, vibration, acceleration, pressure, temperature, and many other physical phenomena in ways that will be extraordinarily useful across a wide range of human endeavors. New sensors for sound, visible light, infrared, and extremely low light, combined with ever faster and cheaper digital signal processors, will make large-scale system sensing practical and commonplace.
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From page 35... ...
For the purposes of this report, the committee assumed that the technology will be associated with large markets but that part of the research and development challenge may relate to lowering costs for a given level of performance or quality. One area of uncertainty about EmNet markets relates to instances where an EmNet may have a broad public benefit that cannot be easily captured by one or more vendors.
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From page 36... ...
In this report, the committee focuses explicitly on networked systems of embedded computing devices, while acknowledging that many of the issues that arise with stand-alone systems will be relevant in the networked arena as well. While the research recommendations and discussion in this report can and should be seen as part of a larger networking research agenda, the emphasis here is on EmNets that are purposefully built to perform specific sets of tasks, as opposed to ad hoc interconnections of PDAs and laptops for general-purpose application support.
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From page 37... ...
They are also, by their very nature, networked, power-constrained, and mobile as the cell phone moves around in the physical world, real-time handoffs are made between the various transceiver towers so as to keep the user continuously connected to a given phone call. Cellular telephony can provide a number of valuable lessons for the design and operation of EmNets, but there are also circumstances specific to cell phones that the committee believes will cause some of its solutions to be inapplicable to the kinds of EmNets anticipated here.
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1998. Precision Agriculture in the 21st Century: Geospatial and Information Technologies in Crop Management.
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