I agree with one point, that an event could be impersonated, such as for example "it's getting dark", even if I don't understand the sense of such a structure unless a context (environment of the event) is defined (therefore the event is belonging to this environment by default). That event becomes a context once we connect (attach) to some entity (environment, personal, object, etc.), e.g. "Boris is observing that Turin is getting dark", thus it becomes the context of Turin and transitionally of Boris located (by location) in Turin. Until here we don't have conflict. But then for the rest, we have a serious conflict in basic foundation of data structures. An entity is an attribute of an event from event-centric world, while an event as a context is an attribute of an entity-centric context-aware world. I am not a guru, what I may just say that the event may never happen (never getting dark), while the context will still exist (Turin is in light) and such that I would prefer to convert (eventual) events to the context and not vice-versa starting the context from events that may never exist as from example before), otherwise we risk to lose important data (context). However I don't exclude that events might be generated by the context, when that context is changing, thus we have Turin's context, which is changing from light to dark and this generates the event "getting dark", which we may detach from Turin (impersonate) and say that the default environment is Turin, then there is no need to explicitly say "Turin is getting dark", which is also a context (status of Turin). Of course it depends on definition of the event and we may say that the measurement of the light leading to the context of Turin (Turin is in light) is also an event, but then we may say that Turin is in light (therefore don't need a measurement as event) is a fact without any measurement (no events). Thus, materialism or idealism, chicken/egg problem :). Please pay attention to this, otherwise we risk to create troubles for ourselves in future. I suggest we take a decision, and make an assertion in certain sense, saying that an event may become a context when assigned to an entity and not that event has an attribute, which is an entity assigned to this event. Then we would have an event (no entities - no attributes), once this even obtains an entity it become a context. I see only this solution to solve this. Then everything become clear, changing in the context may generate an event, and if we cancel the entity from the event it transforms back to the event. I don't know however how to realize and achieve it on the practical level, I believe products will be impacted. But we have to do this, otherwise we will have probably some difficulties in the P/S GE as well, that will be confused what is the data structure and where are the attributes. Boris From: Guy Sharon [mailto:GUYSH at il.ibm.com] Sent: Friday, January 06, 2012 1:37 AM To: fano.ramparany at orange.com Cc: Moltchanov Boris; Licciardi Carlo Alberto; Fiware-data at lists.fi-ware.eu; jhierro at tid.es Subject: RE: [Fiware-data] FI-WARE-data / VisionDocument / Data-Context-Eventdefinition - a proposed revision of the Event definition Good idea to start drawing things. But this is far from what I was trying to convey. In fact, I now understand that we need to touch \ sync on a fundamental point about events. Events must be treated as first class citizens in models and transports - not incorporated into entities\things and collapsed into properties rather they should exist alongside entities and may be associated with entities. I will try to give an example through three cases - 1) the simple one with the boiler, 2) an event to many entities with a check deposit, and 3) many events to one entity with the TVSet. If needed a drawing board and a discussion could be a good idea to resolve this in Madrid. First a simplified ontology view of the three cases 1) [cid:image001.gif at 01CCCC8A.81645090] 2)[cid:image002.gif at 01CCCC8A.81645090] 3)[cid:image003.gif at 01CCCC8A.81645090] Now lets look at how an event then should be represented as in the Vision of the chapter and how they would be stored or communicated versus entities. 1)[cid:image004.gif at 01CCCC8A.81645090] These may actually be 2 different views on all the data that gets collected (repository) First view through the eye of an entity - you would see all the temperature values over time Second view through the eye of an event - you would see all the TemperatureMeasured events over time and what temperature reading they provided to what Boiler 2) Here - it is IMPORTANT to keep all the 'properties' of the event together (even though they are associated to different entities) for proper event processing - this is for some event processing implementation a real big issue when they decouple especially when you need to reason over the events and not over the entities it may have been associated with. [cid:image005.gif at 01CCCC8A.81645090] These may actually be 2 different views on all the data that gets collected (repository) First view through the eye of the entities - each entity will show all its properties by property over time Second view through the eye of an event - you would see all the events over time with all the relevant 'properties' that are associated to different entities - together. 3) Here - it is IMPORTANT to distinguish between different events with 'properties' that are associated to the same entity property. [cid:image006.gif at 01CCCC8A.81645090] These may actually be 2 different views on all the data that gets collected (repository) First view through the eye of an entity - you would see all the location values over time regardless of the type of event Second view through the eye of an event - you would see all the events over time and what location the TVSet is according to the event types. Regards, Guy Sharon Manager Event-based Middleware & Solutions ________________________________ Phone: 972-4-8296587 | Mobile: 972-54-6976417 E-mail: GUYSH at il.ibm.com<mailto:GUYSH at il.ibm.com> Website: www.research.ibm.com/haifa/dept/services/soms_ebs.html<https://www.research.ibm.com/haifa/dept/services/soms_ebs.html> Find me on: [cid:image007.jpg at 01CCCC8A.81645090] <http://www.linkedin.com/profile/view?id=3618230&authType=name&authToken=7XaO&locale=en_US&pvs=pp&trk=ppro_viewmore> [cid:image008.jpg at 01CCCC8A.81645090] <http://www.twitter.com/#!/@guyoser> and within IBM on: [cid:image009.jpg at 01CCCC8A.81645090] <https://w3-connections.ibm.com/profiles/html/profileView.do?key=c22fdae3-0bc2-4626-a30b-095a0eb63ec8&lang=en> [cid:image010.jpg at 01CCCC8A.81645090] <http://cattail.boulder.ibm.com/cattail/#view=guysh@il.ibm.com> [cid:image011.gif at 01CCCC8A.81645090] Haifa University, Mount Carmel Haifa, HA 31905 Israel From: <fano.ramparany at orange.com<mailto:fano.ramparany at orange.com>> To: Guy Sharon/Haifa/IBM at IBMIL Cc: <boris.moltchanov at telecomitalia.it<mailto:boris.moltchanov at telecomitalia.it>>, <carlo.licciardi at telecomitalia.it<mailto:carlo.licciardi at telecomitalia.it>>, <Fiware-data at lists.fi-ware.eu<mailto:Fiware-data at lists.fi-ware.eu>>, <jhierro at tid.es<mailto:jhierro at tid.es>> Date: 05/01/2012 12:13 Subject: RE: [Fiware-data] FI-WARE-data / VisionDocument / Data-Context-Eventdefinition - a proposed revision of the Event definition ________________________________ Hi Guy, Thank you for your comments. Most of my feedback are covered in the joint IoT/Data discussion. I'd just like to bounce on your attempt to describe the boiler example using the data/context/event schema. When you say "you treat temperature and pressure as attribute.... Is fine with me - but is irrelevant to the above representation", do you mean that you would handle this differently? In which case could you elaborate? Here is my proposal: [cid:image012.png at 01CCCC8A.81645090] Which in the graphical notation corresponds to: [cid:image013.jpg at 01CCCC8A.81645090] My point is that it seems more natural to consider the 3 "DataElementAttribute" boxes in the middle as events, than to call the entire graph an event. In my proposal the links are bidirectional, which makes It possible to retrieve the DataElement from the DataElementAttribute. Any comment or alternative viewpoint welcome, Kind regards, Fano De : Guy Sharon [mailto:GUYSH at il.ibm.com] Envoyé : mardi 3 janvier 2012 20:51 À : RAMPARANY Fano RD-TECH-GRE Cc : boris.moltchanov at telecomitalia.it<mailto:boris.moltchanov at telecomitalia.it>; carlo.licciardi at telecomitalia.it<mailto:carlo.licciardi at telecomitalia.it>; Fiware-data at lists.fi-ware.eu<mailto:Fiware-data at lists.fi-ware.eu>; fiware-data-bounces at lists.fi-ware.eu<mailto:fiware-data-bounces at lists.fi-ware.eu>; jhierro at tid.es<mailto:jhierro at tid.es> Objet : Re: [Fiware-data] FI-WARE-data / VisionDocument / Data-Context-Eventdefinition - a proposed revision of the Event definition Fano, I think the discussion you raise brings up the aspect of the semantic meaning of an event and the representation of an event. In the definition of an event in our chapter we discuss the representation of an event and not the semantic meaning of an event. An event may represent change of and attribute value of some entity. It can also mean a change in state \ transition. But how do you communicate the event of an attribute change for example... You would provide an event which is a specific Data Element that consists of Data Element attributes that may include info on the entity for an attribute is being changed, the attribute that is being change, the old value of the attribute, the new value of the attribute, the time during which the change occurred, etc. Therefore the event representation - how the event is communicated between GEs for example is a specific Data Element. In your example there are 2 types of events - TemperatureMeasured and PressureMeasured TemperatureMeasured consists of tempValue, timeStamp and boilerID attributes - for example I think you refer more to the semantical or ontology level of the event which in my opinion is not covered by the whole Data Element discussion. >From that point based on the example - we have an event associated with temperature of a boiler and another associated with the pressure of the boiler - here you treat temperature and pressure as attributes of the boiler and events associated to these attributes - which is fine with me - but is irrelevant to the above representation. In other words - event element attributes tempValue, boilerID of the event element TemperatureMeasured are semantically mapped to the Boiler. An event could carry information relevant to more than one entity you wish to model which in that case the event does not represent a change in attribute but perhaps something more abstract - a situation! The output of event processing is also an event - a complex event - that may not be associable to an attribute or rather is associated to multiple attributes of multiple entities. Regards, Guy Sharon Manager Event-based Middleware & Solutions Group ________________________________ [cid:image014.gif at 01CCCC8A.81645090]<http://www.ibm.com/smarterplanet> Event-based Middleware & Solutions<http://www.haifa.il.ibm.com/dept/services/soms_ebs.html> phone : +972 4 8296587 mobile : +972 54 6976417 address : IBM R&D Labs in Israel, Haifa University Campus, Mount Carmel, Haifa, 31905, Israel email : guysh at il.ibm.com<mailto:guysh at il.ibm.com> From: fano.ramparany at orange.com<mailto:fano.ramparany at orange.com> To: boris.moltchanov at telecomitalia.it<mailto:boris.moltchanov at telecomitalia.it>, carlo.licciardi at telecomitalia.it<mailto:carlo.licciardi at telecomitalia.it>, jhierro at tid.es<mailto:jhierro at tid.es> Cc: Fiware-data at lists.fi-ware.eu<mailto:Fiware-data at lists.fi-ware.eu> Date: 03/01/2012 20:45 Subject: [Fiware-data] FI-WARE-data / VisionDocument / Data-Context-Event definition - a proposed revision of the Event definition Sent by: fiware-data-bounces at lists.fi-ware.eu<mailto:fiware-data-bounces at lists.fi-ware.eu> ________________________________ Hi, I wish you the best for 2012 and in particular much success to our FIWARE project and to the FI PPP program in general! FT is involved in adding a semantic extension to the Publish/Subscribe GE. One step required is to define a "semantic aware" data schema (*) able to capture the Data-Context-Event model that has been defined in the Vision Document. While revisiting this chapter (the overview chapter: https://forge.fi-ware.eu/plugins/mediawiki/wiki/fiware/index.php/Data/Context_Management#Overview), I felt uncomfortable with the definition of an event, which according to the current version is "specific Data Element" with a timestamp to represent its date/time occurence. However, events are generally related to the creation of "element attributes" or changes in the values of "element attributes" (for example, if the temperature of the boiler has been measured 2 times and its pressure 1 times. There will be 3 events, each of them will correspond to a Context Element attribute. More precisely, 2 context attributes for the two temperature measurements and 1 context attribute for the pressure measurements. The timestamps of those 3 measurements would probably be all different because the measurements would be done at different times. The "element attribute" corresponding to the 2nd temperature measurement will supercede the one corresponding to the 1rst temperature measurement. (Note: with the approach proposed in the working document I refer to below (**), the timestamp is a meta-data associated to the "element attribute"). For this reason I'd like to propose a slight revision of the event definition and state that "an event is a specific Data Element attribute" (with a mandatory timestamp meta data to capture its date/time occurrence). This definition would replace this one: "an event is a specific Data Element". Any comment/feedback on this and on the working document which proposes a flexible ontology which aligns with our data model, is more than welcome, Best regards, Fano (* called an Ontology in the semantic web framework) (** This document proposes an Ontology for Defining Ontologies for the Pu ReleaseV0<https://forge.fi-ware.eu/frs/shownotes.php?release_id=7>. In case the link doesn't work, the document is in FI-WARE->files->OntologyV0.pdf on the FI-WARE fusion forge web site)_______________________________________________ Fiware-data mailing list Fiware-data at lists.fi-ware.eu<mailto:Fiware-data at lists.fi-ware.eu> http://lists.fi-ware.eu/listinfo/fiware-data Questo messaggio e i suoi allegati sono indirizzati esclusivamente alle persone indicate. La diffusione, copia o qualsiasi altra azione derivante dalla conoscenza di queste informazioni sono rigorosamente vietate. 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