  In this paper, we propose a simple generic model to manage time series. A
time series is composed of a calendar with a typed value for each calendar
entry. Although the model could support any kind of XML typed values, in this
paper we focus on real numbers, which are the usual application. We define
basic vector space operations (plus, minus, scale), and also relational-like
and application oriented operators to manage time series. We show the interest
of this generic model on two applications: (i) a stock investment helper; (ii)
an ecological transport management system. Stock investment requires
window-based operations while trip management requires complex queries. The
model has been implemented and tested in PHP, Java, and XQuery. We show
benchmark results illustrating that the computing of 5000 series of over
100.000 entries in length - common requirements for both applications - is
difficult on classical centralized PCs. In order to serve a community of users
sharing time series, we propose a P2P implementation of time series by dividing
them in segments and providing optimized algorithms for operator expression
computation.
