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Research Challenges in Sensor Nets & Pervasive Systems, … and some observations on writing effective grant proposalsNSF NOSS Info Mtg, Oct 19, 2004

Rutgers, The State University of New JerseyD. Raychaudhuri

ray@winlab.rutgers.edu www.winlab.rutgers.edu

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Some Trends

< 2% of all CPUs go into PCs ~ $1/1GB (300 songs, 1 movie) Sensor + radio on single chip (SoC) ~$10 $1 Internet of Things (M2M – machine 2 machine)

Revenue: $2.5B / 2004, $10B / 2008 (FocalPoint) Nestlé: hundreds of ice-cream vending machines 1,000 railcars in Britain transmit maintenance data Philips: Plans to link light fixtures using ZigBee radios

Wireless sensor nets & pervasive computing migrating from research to early usage….

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Internet (IP-based)

Infostation cache

WLANAccess Point

WLANHot-Spot

VOIP(multi-mode)

Low-tier clusters(e.g. low power 802.11 sensor)

Ad-hocnetwork

extension

Public Switched Network(PSTN)

BTS

High-speed data & VOIP

Broadband Media cluster(e.g. UWB or MIMO)

BTS

BSC

MSC

CustomMobileInfrastructure(e.g. GSM, 3G)

CDMA, GSMor 3G radio access network

Generic mobile infrastructure

Today Future

GGSN,etc.

Voice(legacy)

High-speed data & VOIP

Relay node

Wireless Network (R)EvolutionIncreasing use of fast, low-cost short-range radiosHeterogeneous systems with multiple radio standards (3G, 4G, WLAN, UWB..)Increasing use of unlicensed spectrum and dynamic sharing methodsSelf-organizing ad-hoc access networks including mesh, home & sensor netsUniform IP core network as backboneNew socket & network programming models

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Sensor Nets & Pervasive Systems

Mobile Internet (IP-based)

Overlay Pervasive Network Services

Compute & StorageServers

User interfaces forinformation & control

Ad-Hoc Sensor Net A

Ad-Hoc Sensor Net B

Sensor net/IP gatewayGW

3G/4GBTS

PervasiveApplication

Agents

Relay Node

Virtualized Physical WorldObject or Event

Sensor/Actuator

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(Frictionless Capitalism)**2 Find goods and services on your PDA as you walk through town Walk into your dept store and pick up what you need (no cashier!)

“Smart” Transportation systems get routed around traffic jams in real-time receive collision avoidance feedback, augmented reality displays be guided to an open parking spot in a busy garage

Airport logistics and security Walk on to your plane (except for physical security check) Find your (lost) bags via RFID sensors Airport authorities can screen passenger flows and check for unusual patterns

Smart office or home Search for physical objects, documents, books Maintain a “lifelog” that stores a history of events by location know where your co-workers and family members are

Pervasive Systems: Applications

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Pervasive Systems: Properties Robust operation

Self-healing, self correcting Probabilistic guarantees, soft state

Ad-hoc & heterogeneous Multiple owners and objectives Groupings based on dynamic proximity and common goals

Data Centric Data and related context more important than IP address...

Open, evolving Re-purpose, (unplanned) emerging behavior

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Sensors Tiny, low-power, integrated wireless sensors (hardware) Embedded OS and networking capabilities (software)

Ad-hoc wireless networks Self-organizing sensor networks Scalable, capable of organic growth Interface to existing 3G/4G cellular and WLAN Power efficient operation

Sensor network software Dynamic binding of application agents and sensors Real-time orchestration of sensor net resources Robust, secure and failsafe systems

Augmented reality, new displays, robotics, control, information processing...

Pervasive Systems: Key Technologies

emerging computer hardwarecategory, optimized for size/power

new type of wireless network withoutplanning or central control

fundamentally different software model- not TCP/IP Windows or Unix!!

...related application technologies

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Pervasive Systems: Layered Model

•••

•••

•••

•••

•••

•••

•••

<>

<>

<>

<>

<>

<>

<>

Sensors & Actuators

Ad-Hoc Data Network

Overlay Service Network

Autonomous AgentsAffinityGroups

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Sensor Networks: Software Model Sensor net scenarios require a fundamentally new software

model (…not TCP/IP or web!!): Large number of context-dependent sources/sensors with unknown IP address Content-driven networking (…not like TCP/IP client-server!) Distributed, collaborative computing between “sensor clusters” Varying wireless connectivity and resource levels

Sensor NetSoftwareModel

Pervasive Computing ApplicationPervasive Computing Application

Agent 2Agent 1

Agent 3

SensorCluster A

SensorCluster B

Run-timeEnvironment(network OS)

ResourceDiscovery

Ad-hoc Routing

OS/ProcessScheduling

Overlay Network for Dynamic Agent <-> Sensor

Association

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Sensor Networks: Ad-Hoc Wireless for Basic Connectivity

Self-organizing ad-hoc networks serve as the low-tier infrastructure for pervasive systems.

Maturing topic, but research opportunities do exist, for example: Better MAC algorithms for ad-hoc mode Topology discovery and self-organization protocols Scaling, hierarchies and spectrum reuse Supporting QoS at MAC and routing layers Cross-layer transport and routing protocols

Relay Node

Access Point

Sensor

Wireless link withvarying speed and QoS

Local Interferenceand MAC Congestion

Dynamically changingNetwork topology

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Sensor Networks: Overlay Services for Dynamic Binding

Overlay networks can be used for dynamic binding between sensor devices, end-users and application programs

Use of XML or similar content descriptor to specify sensor data and application profile “Layer 7” overlay network (implemented over IP tunnels) provides binding service

between producers (sensors) and consumers (servers, users)

Content ConsumerContent Provider

OverlayRouter

A

Interest Profile

XMLDescriptor Overlay

RouterB

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Sensor Networks: Process Orchestration Sensor net applications can involve complex real-time interactions between numerous

network entities Data from each sensor is not necessarily a continuous field measurement Requires context & location aware binding of application with sensors & actuators Orchestration of computing and network resources in real-time

Campus Parking Service

Data Center

Check registration,Deduct parking fee

Allocate closest available space

Check parking space availability

Incoming Car ( check ID: Registered student/faculty/staff, guest reservation? Fee

deduction)

Look for parking space: subscribe (plate-num, car-type, IAB guest)

Look for parking space subscribe (plate-num, car-type, student)

Monitorincoming car

Monitoravailable space

Parking Center

Figure courtesy of Prof. Manish Parashar

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Pervasive Systems: Information Management

Sensor

Multi-tiered aggregation of data into actionable informationsignificant technical challengesin distributed data processing...

Figure courtesy of Dr. Max Ott

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Sensor Systems: Performance Evaluation Significant challenges in validation and

performance evaluation of sensor systems Large scale ~100’s to 1000’s of nodes Need for realistic wireless connections Should incorporate CPU processing limitations Energy as a key performance metric Systems with emergent behavior

Motivates scalable simulation models, emulator systems and real-world testbeds for sensor nets

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NSF Community Testbeds: ORBIT Radio Grid

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NSF Community Testbeds: ORBIT Field Trial System

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Some NOSS Related Research Topics: Sensor network software architecture

Ad-hoc network protocols: energy, cross-layer, hierarchies... Distributed OS & new sensor net API’s Data-centric network services & programming model

Location-aware networking & applications Location determination in wireless networks MAC and routing protocols which exploit location Location middleware and applications

Privacy & security in sensor nets Hiding location and context for privacy Developing trust in ad-hoc networks New security models for sensor applications

Large-scale sensor nets Scalability of large-scale networks Stability under different types of traffic overload and failures Emergent behavior of autonomous protocols & applications

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Writing Effective Systems Proposals

Important Disclaimer:This material is being provided the request of the NSF program officer with the objective of assisting new faculty in getting started withwriting responsive proposals. The author recognizes that the outlined approach is by no means unique and is not intended for experiencedNSF-funded researchers who are likely to have their own well-developed methods.

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Preliminary Work: Initial Preparations

Start early: read NSF call for proposals carefully as soon as it is issued and understand the research direction/emphasis

Critically evaluate your research concepts vs. scope of CFP to make sure there is a fit

Start to study and define a “systems vision” corresponding to the research focus you have in mind Builds understanding of system scenarios and related open problems Helps clarify practical constraints of scenarios under consideration Provides a holistic framework for your proposal Valuable step even if your research idea is more narrowly focused

…often requires a prior discussion and research investment of ~1 yr+ to respond to the CFP for a new area

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Step 1: The Research Idea Define your specific research theme in context of

the systems vision discussed earlier What specific problem is being solved and exactly how does it fit into the

system under consideration?

Carefully evaluate importance of your ideas relative to prior work and “big picture” of target system Define your research contribution clearly in terms of new technologies,

system models, algorithms, methodology and how it helps solve open problems

Is this a conceptually new idea and does it break new ground in the area? Is this a sincere attempt to solve a new research problem, or an attempt to

recycle a favorite model or methodology?

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Step 1: The Research Idea (contd.) Evaluate the functional and performance

benefits of the proposed idea, and back it up with preliminary results if at all possible: What are the system level performance gains ..10%, 50%, 100%, 10x,

100x? If the benefits are more complex (e.g. ease of implementation, software

robustness or scalability), how would you assess these advantages? Is this a sincere attempt to solve a new research problem, or an attempt

to recycle a favorite model or methodology?

Be critical with your own work…! Discussions with colleagues, mentors always beneficial.

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Step 2: The Research Project

When the research idea has passed internal critical review, you need to work on defining the project

Remember that defining the research project is not the same as simply describing the research idea: Requires clear definition of scientific and technical objectives of the project Does the project result in: analysis, modeling, system design, hardware design,

protocol definition, performance analysis, proof-of-concept prototyping, …? What methodologies are used for the project? What are the metrics used to determine whether the proposed idea works? What specific technical results are expected as the outcome? Is this a collaborative project? If so, identify respective roles and interfaces.

Collaboration is often the best way to address a complex research problem…

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Step 3: The Research Plan

Once you have defined the research project in terms of high-level objectives, create a solid project plan: Identify major project sub-tasks and their milestones; this is useful even for a

simple analytical project and mandatory for anything more complex Make bottom-up estimates of the time required for each subtask taking into

account planned level of resources Identify equipment, simulation software, testbeds, etc. required for project Identify potential delays/risks and dependencies between tasks Construct an overall schedule and set of milestones based on above Identify broader impacts, educational activities & other factors required by NSF

Use the this information to prepare a project budget (…which should reflect the project plan and not be a template for x summer mo & y graduate students)

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Step 4: The Research Proposal

The research proposal follows nicely once you have the content from the previous slides: Technology context & system scenarios under consideration Main research idea, its relevance and competitive evaluation Research project as defined by objectives, methodology, results Research plan, schedule & budget References

Writing the proposal is, of course, the final important step Prepare an early draft & leave time for discussion and improvement Rewrite again and again for clarity, logical flow and content Be concise and avoid using jargon to the extent possible Never cut-and-paste from other material! Get internal peer-review, collaborate in writing and make multiple revisions