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OpenMI Award presented to KISTERS

January 11, 2011

Model in Denmark linked to server in Germany via standardized interface makes web interoperability vision a new reality.

Open Modeling Interface (OpenMI) is an association and a software standard that takes integrated modeling a step further. It allows models to exchange data on a time step by time step basis as they run.

This past year, in 2010, KISTERS’ Time Series Server (KiTSM) became OpenMI compliant. Raw and processed time series data for any water resource related observation is now accessible for OpenMI-compliant models. To put this new capability to the test, HydroInform successfully linked a model in Denmark with KISTERS’ TSM Server in Germany via the internet. This proof of concept makes the vision of data hubs serving freely accessible and qualified time series data through a standardized interface a reality.

In May, 2011 on behalf of the OpenMI Association executive committee, Quillon Harpham announced that KISTERS received the 2010 OpenMI Award.

Proof of Concept

The OpenMI extension link compliant models or modules to WISKI, KISTERS’ data repository. Compliant models can retrieve any source of time series data, either processed or raw data, through the local area network or internet. Users simply install a WISKI linkable component on the local computer, after which this component can be included in OpenMI configurations on the local computer. When the configuration is running, the local WISKI linkable component communicates through the Internet with WISKI located on a remote server.

An example of practical implementation could be a flood forecast system (e.g. rainfall-runoff models and river models) running at the premises of the local authorities and pulling the most recent meteorological data through OpenMI from a remote WISKI server.

Furthermore this development establishes a proof of concept for new ways to use OpenMI. From the very beginning OpenMI was conceived to dynamically connect anything to anything anywhere. The OpenMI standard has always supported such applications, but most applications have been model to model linkages, running locally — until now. The migration of WISKI has demonstrated the applicability of OpenMI for remote linking and standardized access to databases.

Proxy Design Pattern

The migration was done using a proxy design pattern. The KiTSM proxy is responsible for remote communication with the KiTSM server. The OpenMI wrapper implements the linkable component interface and is accessed from the local model through OpenMI methods. The benefit of this approach is the internet communication using private protocol, which is optimized for communication between the proxy and the server — whereas the wrapper can be accessed by any OpenMI compliant component/model.

KiTSM can contain thousands of time series and exposes all inventory as OpenMI exchange items. This could potentially make the OpenMI configuration process very slow. To overcome this problem, the KiTSM site, station, and parameter of interest are defined in the OMI file, so only time series for this combination are exposed.

Moreover the OMI file also contains the information needed for the proxy to connect to the server (IP-address and credentials). In this way the user can simply select the KiTSM OMI file, which is stored on the local computer, configure and run it without worrying that this component actually gets its data from a remote server. Everything runs as if all components were installed locally.

HydroInform assisted KISTERS in the OpenMI migration of KiTSM. Also, here, the proxy design pattern turned out to be beneficial. Developers from KISTERS created the proxy, which then was installed on a local computer at the HydroInfom offices. HydroInfom then developed and tested the OpenMI wrapper as if the KiTSM was locally installed.

Special thanks to Jan Gregersen (HydroInform) and Michael Natschke (KISTERS AG) for contributing this article.