Transcript Reasonable sales price? Item description?

國立雲林科技大學
National Yunlin University of Science and Technology
A support system for predicting
eBay end prices
Presenter : Shu-Ya Li
Authors : Dennis van Heijst, Rob Potharst, Michiel van Wezel
DSS 2008
Intelligent Database Systems Lab
Outline

Motivation

Objective

Methodology

Experiments and Results

Conclusion

Personal Comments
N.Y.U.S.T.
I. M.
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Intelligent Database Systems Lab
Motivation

N.Y.U.S.T.
I. M.
The market price of a product is generally non-stationary at
eBay — it fluctuates over time.
How to make the auction be easier?
Buyers
•Many bargains
•How to check prices of items?
Sellers
•Reasonable sales price?
•Item description?
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Intelligent Database Systems Lab
Objectives


N.Y.U.S.T.
I. M.
Finding these bargains can be made easier by using a support
system.
We create a support system for predicting end prices on eBay.
End price
Buyers
bargains
 •Many
 •Check prices of items
Sellers
sales price
 •Reasonable
 •Item description
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Intelligent Database Systems Lab
Methodology
N.Y.U.S.T.
I. M.
1. Input Data
3. LSBoost
Feedback rating
•Feedback rating
•Number of pictures
•Item description
x
Number of pictures
2. CART
Number of
pictures
Prediction
price
Feedback rating
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Intelligent Database Systems Lab
CART (Classification And Regression Trees)

N.Y.U.S.T.
I. M.
CART

A binary tree.

Each decision node has two child nodes, which may again be decision
nodes or leaf nodes.
Feedback rating ≦100
Yes
No
Feedback rating ≦120
Number of pictures≦5
Yes
No
Yes
No
Number of pictures≦10
$900
6
Yes
No
$1,100
Intelligent Database Systems Lab
Experiments
N.Y.U.S.T.
I. M.
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Intelligent Database Systems Lab
Conclusion
N.Y.U.S.T.
I. M.

The predictions are based on a boosting model, which uses
closed auctions of some product to predict prices for
current auctions of the same product.

Sellers can use this system to




submit draft versions of eBay auction pages.
get an indication of a reasonable sales price.
get the hints on terms to include in their ad text.
Buyers can use this system to

check prices of items they have interest in and to locate bargains.
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Intelligent Database Systems Lab
Personal Comments

Advantage


…
Drawback


N.Y.U.S.T.
I. M.
…
Application

Hedonic Price

Investment
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Intelligent Database Systems Lab