Databases Reference
In-Depth Information
of prolix RDF features or usage of slash-URIs can help determine the performance of a
dataset. Additional metrics are low latency and high throughput of the services provided
for the dataset.
Example.
In the use case example, the target performance may depend on the number
of users, i.e. it may be required to be able to server 100 simultaneous users. Our flight
search engine will not be scalable if the time required to answer to all queries is sim-
ilar to the time required when querying the individual datasets. In that case, satisfying
performance needs requires caching mechanisms.
Definition 24 (Security).
Security can be defined as the extent to which access to data
can be restricted and hence protected against its illegal alteration and misuse. It refers
to the degree to which information is passed securely from users to the information
source and back.
Metrics.
Security can be measured based on whether the data has a proprietor or requires
web security techniques (e.g. SSL or SSH) for users to access, acquire or re-use the
data. The importance of security depends on whether the data needs to be protected and
whether there is a cost of data becoming unintentionally available. For open data the
protection aspect of security can be often neglected but the non-repudiation of the data
is still an important issue. Digital signatures based on private-public key infrastructures
can be employed to guarantee the authenticity of the data.
Example.
In the example scenario, let us consider a user who wants to book a flight from
a city A to a city B. The search engine should ensure a secure environment to the user
during the payment transaction since her personal data is highly sensitive. If there is
enough identifiable public information of the user, then she can be potentially targeted
by private businesses, insurance companies etc. which she is unlikely to want. Thus, the
use of SSL can be used to keep the information safe.
Definition 25 (Response-time).
Response-time measures the delay, usually in seconds,
between submission of a query by the user and reception of the complete response from
the dataset.
Metrics.
Response-time can be assessed by measuring the delay between submission of
a request by the user and reception of the response from the dataset.
Example.
A user is looking for a flight which includes multiple destinations using the
example flight search engine. She wants to fly from Milan to Boston, Boston to New
York and New York to Milan. In spite of the complexity of the query the search engine
should respond quickly with all the flight details (including connections) for all the
destinations.
Representational Dimensions.
Representational dimensions capture aspects related
to the design of the data such as the
representational-conciseness
,
representational-
consistency
,
understandability
,
versatility
as well as the
interpretability
of the data.
Definition 26 (Representational-conciseness).
Representational-conciseness refers
to the representation of the data which is compact and well formatted on the one hand
but also clear and complete on the other hand.
