declarative sensor networks with applications in landslide detection

declarative sensor networks with applications in landslide detection i. CAST/CMU/TRUST Joint Conference 9 January 2007 David Chu Computer Science Division EECS Department UC Berkeley

context Sensor Networks 10’s – 1000’s – 10, 000’s Leach's Storm Petrel

context Sensor Networks early experiences

motivation programming sensor networks is difficult! building entire sensor systems is even harder!!

inspiration sensor networks data management network design

inspiration : data management • declarative is widely used in data management – – – • relational databases spreadsheets abstract “what” from “how” (Sensor-Network-As-Database)

inspiration : network design • declarative is new idea in networking – – • compact flexible analyzable, optimizable Internet Routing, Overlays built declaratively (the P 2 project)

inspiration sensor networks data management ( DSN ) network design

what we did • adapted declarative language • built compiler & runtime for sensornets • wrote declarative examples

… from original Trickle paper … DSN specification 10 x 6 topology 30 x 2 topology

agenda 1. language overview 2. declarative sensornet examples 3. system architecture 4. feasibility assessment 5. application to landslide detection

brief language overview Rule 1: implies Rule 2: Fact: Built-ins: join don’t care

a full example : tree S C 1 Z S C 2 C D D

and others… geographic routing* *fallback routing not shown tracking localization link estimator

arch : compiler store(…) : - prod(…), cons(…). … path(…) : - link(…), dest(…). … Snlog Program Snlog Compiler/Optimizer Snlog Frontend Execution Planner nes. C Backend nes. C Templates Generic. Predicate. Template … … Runtime. Template … … Generated nes. C code Database Operators Built-in Predicates nes. C Compiler Runtime Components Type system Network support DSN Runtime Support Binary Image

arch : runtime Join Proj runtime daemon tupleready … … Sel tupleready … … Ag … Proj sendready tupleready mac daemon Join Proj Sel Agg database operators (compiler’s library) table (compiler generated) builtin (user’s library) the network push interfaces pull interfaces thread of control event signal

implementation challenges • predictable execution → dynamic vs. static allocation • memory constraints → memory footprint optimizations no temporary tables, join/agg operator choice • asynchrony → rule-level atomicity priorities

evaluation

evaluating tree-collection messages sent (similar performance) hop-counts

lines of code

compiled size Telos. B mote code space = 48 KB, data space = 10 KB

VLDB 2006 demo

application large scale and fine-grained debris flow monitoring

[Left] La Conchita, California – a small seaside community along Highway 101 south of Santa Barbara. This landslide and debris flow occurred in the spring of 1995. A reoccurrence in 2005 claimed 4 lives and resulted in 29 missing persons. [Right] Chehalis, Washington - landslides and debris flows during the winter storms of February 1996. Photographs by R. L. Schuster, U. S. Geological Survey.

Day Fire Harvard Burn Site [Above] The locations of the 2005 -2006 and 2006 -2007 debris flow deployment sites. [Top Right] Smoke from the Day Fire. [Middle Right] Recently burned hillside in Burbank, CA was the site of two debris flows in 2005 -2006 Winter season. [Bottom Right] Base of the channel after debris flow with remaining sediment. [Bottom Left] Burn-resilient vegetation is quickly recovering just a few months after the fires and debris flows.

[Above] Parshall flume used in conjunction with water level logger at the channel’s choke-point. [Top Right] Custom overland flow sensor fine-grained detection of water runoff. [Bottom Right] Solarpowered base station for actuating and gathering data from the wireless sensor network, shown here connected to laptop during testing.

conclusion • sensor networks → data + communication • several examples of functional programs • feasible for today’s hardware platforms • preparing for landslide deployment

thanks collaborators Joe Hellerstein, Scott Shenker, Ion Stoica Arsalan Tavakoli, Lucian Popa Tsung-Te Lai Phil Levis, Jung Woo Lee, Aby John Daniel Malmon