Alpha algorithm: Difference between revisions

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It was first put forward by [[Wil van der Aalst|van der Aalst]], Weijters and Măruşter.<ref>van der Aalst, W M P and Weijters, A J M M and Maruster, L (2004). "Workflow Mining: Discovering process models from event logs", ''IEEE Transactions on Knowledge and Data Engineering'', vol 16</ref> The goal of Alpha miner is to convert the event log into a workflow-net based on the relations between various activities in the event log. An event log is a multi-set of traces, and a trace is a sequence of activity names. Several extensions or modifications of it have since been presented, which will be listed below.
 
Alpha miner was the first process discovery algorithm ever proposed, and it gives a good overview of the aim of process discovery and how various activities within the process are executed. Alpha miner was also the basis for the development of many other process mining techniques such as [https://www.researchgate.net/publication/229124308_Process_Mining_with_the_Heuristics_Miner-algorithm heuristic miner], [https://www.researchgate.net/publication/220783863_Genetic_Process_Mining genetic mining] was developed based on the idea alpha miner is built on.<ref name=":002">{{Cite journal|last=van der Aalst|first=W.|last2=Weijters|first2=T.|last3=Maruster|first3=L.|date=September 2004-09|title=Workflow mining: discovering process models from event logs|url=https://ieeexplore.ieee.org/abstract/document/1316839?casa_token=9yHSQACaiPIAAAAA:9q5femdrrRk2ny9aWWLp4H2JRzLm5LcXzlsLZQztTS_0sG_w0pW2y41J1C-tReiZ_uiZdXSKMQ|journal=IEEE Transactions on Knowledge and Data Engineering|volume=16|issue=9|pages=1128–1142|doi=10.1109/TKDE.2004.47|issn=1558-2191}}</ref>
 
Alpha miner was the first process discovery algorithm ever proposed, and it gives a good overview of the aim of process discovery and how various activities within the process are executed. Alpha miner was also the basis for the development of many other process mining techniques such as [https://www.researchgate.net/publication/229124308_Process_Mining_with_the_Heuristics_Miner-algorithm heuristic miner], [https://www.researchgate.net/publication/220783863_Genetic_Process_Mining genetic mining] was developed based on the idea alpha miner is built on.<ref name=":0">{{Cite journal|last=van der Aalst|first=W.|last2=Weijters|first2=T.|last3=Maruster|first3=L.|date=2004-09|title=Workflow mining: discovering process models from event logs|url=https://ieeexplore.ieee.org/abstract/document/1316839?casa_token=9yHSQACaiPIAAAAA:9q5femdrrRk2ny9aWWLp4H2JRzLm5LcXzlsLZQztTS_0sG_w0pW2y41J1C-tReiZ_uiZdXSKMQ|journal=IEEE Transactions on Knowledge and Data Engineering|volume=16|issue=9|pages=1128–1142|doi=10.1109/TKDE.2004.47|issn=1558-2191}}</ref>
 
==Short description==
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== Event log ==
 
 
Event log is the primary requirement for applying any process discovery algorithm. An event log consists of a unique identifier for a case, activity name describing the action occurring in the process and timestamp. An event log can be represented as a multi-set of activities. For the sake of simplicity the following example would use alphabetic letter to represent an activity. Consider an example event log shown in the following figure:
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<math>L1 = [<A,B,C,D>, <A,C,B,D>, <A,E,D>]</math>
 
Every event log can be boiled down into a multi-set of traces, and such traces can be further used to break down relationships between various activities in the process. According to the rules of alpha miner, activities belonging to various cases can have 4 types of relationships between them :<ref name=":02">{{Cite journal|last=van der Aalst|first=W.|last2=Weijters|first2=T.|last3=Maruster|first3=L.|date=2004-09|title=Workflow mining: discovering process models from event logs|url=https://ieeexplore.ieee.org/abstract/document/1316839?casa_token=9yHSQACaiPIAAAAA:9q5femdrrRk2ny9aWWLp4H2JRzLm5LcXzlsLZQztTS_0sG_w0pW2y41J1C-tReiZ_uiZdXSKMQ|journal=IEEE Transactions on Knowledge and Data Engineering|volume=16|issue=9|pages=1128–1142|doi=10.1109/TKDE.2004.47|issn=1558-2191}}</ref>:
 
* '''Direct Succession: x > y''' if and only if some relation x is directly following by y. In our example, we can consider that '''A > B''', '''A > E.'''
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* '''Implicit places:''' Alpha miner cannot distinguish between implicit and required places and thus might result in additional non required places in the discovered petri net.<ref>{{Cite web|title=(PDF) Discovering Petri Nets from Event Logs|url=https://www.researchgate.net/publication/265764352_Discovering_Petri_Nets_from_Event_Logs|access-date=2021-08-31|website=ResearchGate|language=en}}</ref>
* '''Loops:''' Alpha miner cannot discover loops in the process model.<ref name=":1">{{Cite web|title=Limitations of Alpha miner|url=https://courses.edsa-project.eu/pluginfile.php/281/mod_resource/content/0/17%20Alpha%20Algorithm%20-%20Limitations.pdf|url-status=live}}</ref>
* Local dependencies are often missed in alpha miner. <ref name=":1" />
* '''Representational bias:''' Alpha miner can only discover petri net thus adding representational bias such as requirement on unique visible labels for every transition.<ref name=":1" />