Events Flashcards
What are event models used for?
Events are used to model changes in fields, objects and networks.
What questions does event information answer?
Event information answers questions about what happened, what is happening and what may happen. It helps understand and predict what is going on in parts of the world and make decisions to avoid and mitigate undesireable outcomes.
Give some examples of what questions event information might answer?
One might want to know whether it will rain tomorrow (to plan activities) , where s person went after being infected with a dangerous virus (to alert a population at risk) or how long it will take to get through a particular traffic jam (considering alternative routes).
Why have events become increasingly important?
Information in events have become increasingly available often in real time, through sensor measurements. Consequently , events have become important elements of digital information complementing OBJECTS.
What is the difference between events and objects?
Events are different from objects as they capture what happens, not what is. Whether one wants to treat a phenomenon (such as a hurricane) as an object or as an event is an important choice in modelling spatial information.
What are events?
Events can be thought of as processes happening at some time and location. For example a traffic jam is a kind of process occurring at some time somewhere in a street network, and a hurricane is a kind of process happening on a trajectory through time and space.
Transition zones, which is also the case for objects analogously apply to event times capturing their often imprecise beginnings and endings. For example the onset of a traffic jam are not always crisply defined. The analysis of events just like that if objects may or may not require knowledge of their temporal boundaries.
Why are events spatially and temporally bounded?
All events are spatially and temporally bounded I.e. of finite duration and involving partial or whole fields, objects and networks as participants located in space. For example, storms last certain amounts of time in a region and there are times when it has not started or it has already ended as well as regions where it does not happen.
What is the similarity between events and objects?
Events beginning and end may not be known or even knowable, like the boundary of an object
What are the characteristics of an event?
Events have an identity and are described by properties and relations like objects. E.g . Hurricanes get characterised by their properties (such as intensity) and relations (such as those with tornadoes they may have spawned).
Are events he only core concept that captures time?
No, location and all other concepts (fields, objects and networks) all have temporal properties which is also true for the quality concepts (granularity, accuracy and provenance).
What is the reason to understand the spatial and temporal properties of events?
The understand img of event spatial and temporal properties allows for reasoning about their causes and consequences.
For example, floods along a river may be the consequence of rainfall or snow melt in regions upstream.
One should be careful to not infer causation from the temporal precedence or statistical correlation alone, without considering explanatory causal relations which are studied in application domains
Discovering temporal patterns in spatial information often generated domain hypotheses about causes or consequences.
What are the main temporal relations between events?
The main temporal relations are precedence and co-occurrence. For example, a rainstorm can proceed a traffic jam and co-occur with a blackout. In the cases where time is cyclic, (described as weekdays or seasons) mercuric events, also known as episodes, can be defined
What is the key thematic relation of events?
The key thematic relation is participation. The events get located through their participants of events are instances on their part of fields objects and networks. The properties and relations of those participants may get changed through their participation in an event.
For example, storms change the temperature and humidity fields in their area, and traffic jams affect the speed of cars and the properties of roads.
What are complex events?
Parts of events themselves form events, and complex events get aggregated to form simpler ones. Part-whole relations are as central to event-based models as they are to object-based relations.
For example, a tornado may be considered part of a hurricane. There may be questions about maximum wind or damage resulting from a the tornado as well as the total damage of the hurricane.
