Network Traffic Analysis using Traffic Dispersion Graphs - Computer
a traffic analysis tool
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Slide 1 (of 12) a traffic analysis tool Emerson Murphy-Hill, Portland State University, USA
description
a traffic analysis tool. Emerson Murphy-Hill, Portland State University, USA. project background. Maseeh College of Computer Science Portland State University, Oregon, USA. Infopipes Research Project. Group moved from OGI to Portland State within the last year. infopipes project. - PowerPoint PPT Presentation
Transcript of a traffic analysis tool
Slide 1 (of 12)
a traffic analysis toolEmerson Murphy-Hill, Portland State University, USA
Slide 2 (of 12)
project background
Infopipes Research Project
Maseeh College of Computer Science
Portland State University, Oregon, USA
Group moved from OGI to Portland State within the last year
Slide 3 (of 12)
infopipes projecto Infopipes:
o An abstraction for data-streaming
o About data flow, not control flowo Like household water pipes
o Reusable components in streaming applications
Black02
Slide 4 (of 12)
a simple infopipeBuffer
init“initialize my state”super init.queue := SharedQueue new.
pull“answer the first item in my queue”^ queue next
push: anItem“put an item at the end of my queue”^ queue nextPut: anItem.
Slide 5 (of 12)
an open question
Do Infopipes really facilitate reuse in a streaming application?
We don’t know, but let’s build an application and find out…
Slide 6 (of 12)
traffic analysiso Automobile traffic – a good
fit!o Traffic data is a continuous
stream that can be analyzed for current traffic conditions
o A known problem in traffic analysis is measuring truck volume
Slide 7 (of 12)
why measuring truck volume is hard
o Existing roadway hardware is limited
Slide 8 (of 12)
why measuring truck volume is hard (cont.)
Now, how many trucks here?
o 4 trucks, if traffic is moving at the same speed as before
o 4 cars, if traffic is moving slower than before
o Or any combination of cars and trucks, if velocity changes through the sample period!
o So can you determine how many trucks have passed using this hardware?
Slide 9 (of 12)
a method of counting truckso Kwon and colleagues
suggested a method of counting trucks based on two simple observations:
1. Traffic in the innermost lane is often truck-free
2. Velocity in adjacent lanes are correlated over time
Slide 10 (of 12)
for example…
Slide 11 (of 12)
so reconsider the problemNow, how many trucks here?
Slide 12 (of 12)
implementationo We implemented this single
loop truck volume algorithmo We decided to use
Smalltalk/X after ESUG 2004o Some Infopipes can benefit
from in-lined C codeo Simple tests show ST/X is
faster than Squeak
Implementation (cont)o Implementation consists of
a variety of connected Infopipeso Used preexisting, general-
purpose Infopipes (buffers, pumps, tees…)
o Used preexisting, traffic-specific Infopipes
o Created new, traffic-specific Infopipes
implementation (cont)Top-level view:
SqueakSmalltalk/X
SimpleHighwayVehicleClassifierController170 DataLane1..n
Truck CountLane2
Car CountLane2
Truck CountLane3
Car CountLane3
Truck CountLaneN
Car CountLaneN
Car CountLane1
...
Netpipe
Netpipe
Netpipe
Netpipe
Netpipe
Netpipe
Netpipe
HighwayVolumePlot
Truck CountLane2
Car CountLane2
Truck CountLane3
Car CountLane3
Truck CountLaneN
Car CountLaneN
Car CountLane1
...
Output Frequency
Data Source
Mean Estimated Car Length
Mean Estimated Truck Length
DestinationSource
DamperPipe
Time
Time Netpipe Time
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SideEffectPipe- +
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Implementation (cont)o Uses about 50 classes
