Changes for page eMagiz State Generation

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1		-eMagiz Stateful
	1	+eMagiz State Generation

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1		-XWiki.ebakker
	1	+XWiki.CarlijnKokkeler

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9	9
10	10	== 2. Key concepts ==
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12		-All concepts are discussed in the section below..
	12	+In this microlearning, the concept of state generation will be explained.
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14		-== 3. Introducing Stateful ==
	14	+== 3. Definition ==
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16		-Within eMagiz there is a capability to store pieces of data of a specific object that is transit between systems. The basis idea of messages that are processed by eMagiz is that all of these are in transit. However, in certain cases it is very helpful to preserve a state of an object. That state can help to influence the next data packets that are passing through or trigger a certain action for another system.
	16	+State generation concerns the generation of a stateful application or service. This means that, for the application or service to function, data is stored and past states are used to derive information. Such a state may e.g. be a temperature or heartrate measure. Stateful applications or services are opposed to stateless applications or services, which do not require data to function and merely represent the current state.
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18		-An example might be a situation where a sensor is submitting temperature data every 5 seconds on a data stream towards eMagiz. The interesting state of the machine where the sensor is attached to is the average temperature in the last hour. In this case the temperature that is send to the eMagiz should be used to update the state of the machine, and more specifically the average temperature. One needs a data stream from the sensor, a way to aggregate & average out all messages from the last hour, and a way to store the state. Once the temperature reaches a certain threshold, the data is submitted to a next system to raise an alert for a user.
	18	+An example of a stateful application, is an application that obtains temperature measures in a room and presents a timeline of the temperature measures. A thermostat produces the temperature in this example, after which the data needs to be put into context, including the time at which a certain temperature was measured and the room in which it was measured. Then, the data can be evaluated over time, and tested against the norm. This ensures that real time actions can be generated, e.g. a fire alert can be generated when the temperature has risen by 25 degrees Celsius in 1 minute.
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20		-Another example might be a data stream that registers a click on a specific webpage. That data stream is connected to eMagiz, whereby the state of that specific webpage is updated with the number of clicks. Once the number of clicks in the last 30 minutes reaches for instance more than 50, a specific action might be triggered. If that page contains a product, the action might be to display the number of web users active on that product in order to influence the sales of that product. One needs a data stream, a way to count the number of click, and a way to store the state of that webpage.
	20	+== 4. Benefits and Operations ==
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22		-The example are purely illustrative to understand the concept.
	22	+TBenefits of real time state generation are, first of all, that data can be provided immediately and is always up-to-date. Secondly, it is possible to take real time action and take real-time decisions. Lastly, there is no need to store data unnecessarily.
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24		-==== 3.1 State Store ====
	24	+Stateful data can be generated through four main operations. First of all, through enriching data. This means that information should be added to the data, so that it has more meaning. This can be achieved by storing states in a database. For example, when it is known that, if a person works from home, this is stored as A, and if a person works in the office, this is stored as B, the data can be enriched with ‘Home’ and ‘Office’. To ensure this, a database should be present storing the connection between A and Home, and B and Office.
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26		-The state store refers to the storage location of the states of the specific objects in the environment. That storage location is part of the eMagiz platform, and embedded in the eMagiz runtime for now. The user needs to define what objects and the attributes of that object are to be stored. Several different objects and states of the objects can be be defined & stored. A state store can be shared across multiple processes that are allowed to update the state of an object.
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	26	+[[image:Main.Images.Fundamental.WebHome@fundamental-stategeneration-example-enrich.png]]
28	28	==== 3.2 State Operations ====
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30	30	Once the state store is defined, one needs different operations in order to update the state effectively.