Data Sharing System for E-Government - IIMS Solution
1.3.2 Centralized metadata Server.
Some systems manage metadata and data together at same location. When there are multiple data servers and a large number of datasets, searching metadata have do be done from each location. This may cost much time and add burden to each data server because each data server has to respond to search request even no data of interest available. This way may also make many difficulties to keep a compatibility of metadata from different data servers.
IIMS allows data from multiple data servers to be registered to a centralized metadata server. Through a centralized metadata server, IIMS can quickly search all available data from integral metadatabases. IIMS data servers don’t need to serve for data search but only serve for data access. Furthermore, as described in the following, IIMS also provides a gateway (Data Exchange System) to support unified search over multiple metadata servers.
1.3.3. Integrating multiple metadatabases from different metadata servers.
A standard IIMS configuration is a metadata server with multiple data servers. This is called an IIMS Data Sharing System (DSS). However in certain cases, multiple such DSS systems are needed. The reason for multiple DSS could be one of the following:
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There are multiple organizations each independently established its own IIMS DSS system. So each has its own metadata server.
- Different groups have different metadata standards and management rules; this makes a single metadata server impossible.
- For a large organization, particularly with geographically distributive branches, the metadata volume could be too large to be hosted by a single metadata server.
When the organizations want to promote high-level data sharing among their internal IIMS DSS systems, IIMS provides a solution with IIMS Data Exchange System (DES) that enables multiple metadata servers to be searched integrally.
The purpose of IIMS DES is to allow data search and exchange among multiple metadata servers of IIMS DSS. It is like a gateway to allow user easier search through multiple DSS systems each with a metadata server. Each metadata server can contain multiple metadatabases, and those metadatabases may have different metadata standards and definitions.
1.4 On-Line Data Processing
This will be an important feature of IIMS future version. IIMS will support data to be processed on-line when demanded by client at uploading to and downloading from IIMS data server. This feature allows the following extensions for specific applications:
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Dynamic distributive database connection;
- On-line data encryption/decryption for enhanced data security;
- On-line data compression to reduce server space usage and data downloading time;
- On-demand data extraction for remote sensing imagery, digital maps, OLAP, etc.;
- Data format conversion; and
- Accounting for data on-line trading (e-commerce).
1.5 Data Security
Apart from server security, the archived data shall be properly protected because:
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- Owner wants only authorized persons to modify its data when necessary.
- Owner requires that its data are only seen and used by certain people, because of non-disclosure restrictions, or for the purposes of selling data.
- User needs to be sure the data are the original version published by its owner.
IIMS provides the following flexible security measures to assure security and authority to access IIMS servers and the data:
- User account will be verified through a central user database at IIMS metadata server when accessing metadata or data from any registered distributive data server. User doesn’t need to be registered repeatedly to each data server.
- Only the users authorized by system manager can upload data files to a data server. This helps to prevent illegal occupation of disk space at data servers.
- The owner of a dataset can allow only users belong to certain user groups to be able to view and access its data. The catalog will be hidden from users who have no authority to access the dataset. The owner can also assign only certain users to have the authority to modify the catalog and the linked dataset. This function allows a user to assign different security-level to each dataset with maximum flexibility. For example, financial report dataset may be only assessable to high-rank officials; planning map dataset may be only available to planners before publication, while announcement dataset can be opened to every staff.
- Data files at a data server can not be accessed directly, but must through the IIMS data server access service. Thus, all access is under security/authority control of IIMS.
- Each access and operation from IIMS user will be recorded in IIMS log database, IIMS manager can read the log information to monitor and trace illegal use of system and data.
- Concurrent editing of a dataset is controlled by locking/unlocking functions to make sure the modification on data is not lost.
- Data user can query IIMS to show real owner information to assure no fake data publication.
- As a supplementary security, data owner could make its dataset encrypted when uploading to IIMS. Users shall then contact the owner to get a proper key to decrypt the dataset at downloading.