Updated README after many new insights
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README.Rmd
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README.Rmd
@ -22,7 +22,7 @@ layout. The table was installed at the institute in October 2016 and since
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November 2016 log files from interactions of visitors of the museum have
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been collected. These log files are in an unstructured format and cannot be
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easily analyzed. The purpose of the following document is to describe how
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the data haven been transformed and which decisions have been made a long
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the data haven been transformed and which decisions have been made along
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the way.
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# Data structure
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@ -66,9 +66,9 @@ data when further processed and are only in the raw log files.
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The first step is to parse the raw log files that are stored by the
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application as text files in a rather unstructured format to a format that
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is better handled. The data are therefore transferred to a spread sheet
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format. The following section describes what problems were encountered
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while doing this.
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can be read by common statistics software packages. The data are therefore
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transferred to a spread sheet format. The following section describes what
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problems were encountered while doing this.
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## Corrupt lines
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@ -77,9 +77,9 @@ that says
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```
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Warning messages:
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incomplete final line found on '_2016/2016_11_18-11_31_0.log'
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incomplete final line found on '_2016/2016_11_18-11_38_30.log'
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incomplete final line found on '_2016/2016_11_18-11_40_36.log'
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incomplete final line found on '2016/2016_11_18-11_31_0.log'
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incomplete final line found on '2016/2016_11_18-11_38_30.log'
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incomplete final line found on '2016/2016_11_18-11_40_36.log'
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...
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```
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@ -88,17 +88,143 @@ content. It is unclear why and how this happens. So when reading the data,
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these lines were removed. A warning will be given that indicates how many
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files have been affected.
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## Units of the variables
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## Extracted variables from raw log files
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* Welche Einheit haben x und y? Pixel? --> yes
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* Welche Einheit hat scale? --> some kind if bit, does not matter, when
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calculating a ratio
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* rotation wirklich degree? --> yes
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* Nach welchem Zeitintervall resettet sich der Tisch wieder in die
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Ausgangskonfiguration? --> PM needs to look it up
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The following variables (columns in the data frame) are extracted from the
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raw log file:
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* `fileId`: Containing the zero-left-padded file name of the raw log file
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the data line has been extracted from
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* `folder`: The folder names in which the raw log files haven been
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organized in. For the HAUM data set, the data are sorted by year (folders
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2016, 2017, 2018, 2019, 2020, 2021, 2022, and 2023).
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* `data`: Extracted time stamp from the raw log file in the format
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`yyyy-mm-dd hh:mm:ss`.
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* `timeMs`: Containing a time stamp in Milliseconds that restarts with
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every new raw log files.
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* `event`: Start and stop event tags. See above for possible values.
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* `artwork`: Identifier of the different artworks. This is a 3 digit
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(left-padded) number. The numbers of the artworks correspond to the
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folder names in `/ContentEyevisit/eyevisit_cards_light/` and were
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orginally taken from the museums catalogue.
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* `popup`: Name of the pop-up opened. This is only interestin for
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"openPopup" events.
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* `topicNumber`: The number of the topic card that has been opened at the back of
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the artwork card. See below for a more detailed descripttion what these
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numbers possibly mean.
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* `x`: Value of x-coordinate in pixel on the 4K-Display ($3840 \times 2160$)
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* `y`: Value of y-coordinate in pixel
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* `scale`: Number in 128 bit that indicates how much the artwork card has
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been scaled (????)
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* `rotation`: Degree of rotation in start configuration.
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<!-- TODO: Nach welchem Zeitintervall resettet sich der Tisch wieder in die
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Ausgangskonfiguration? -> PM needs to look it up -->
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## Variables after "closing of events"
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The raw log data consists of start and stop events for each event type.
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After preprocessing for event types are extracted: `move`, `flipCard`,
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`openTopic`, and `openPopup`. Except for the `move` events, which can occur
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at any time when interacting with an artwork card on the table, the events
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have a hierachical order: An artwork card first needs to be flipped
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(`flipCard`), then the topic cards on the back of the card can be opened
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(`openTopic`), and finally pop-ups on these topic cards can be opened
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(`openPopup`). This implies that the event `openPopup` can only be present
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for a certain artwork, if the card has already been flipped (i.e., an event
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`flipCard` for the same artwork has already occured).
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After preprocessing, the data frame is now in a wide format with columns
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for the start and the stop of each event and contains the following
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variables:
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* `folder`: Containing the folder name (see above)
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* `eventId`: A numerical variable that indicates the number of the event.
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Starts at 1 and ends with the total number of events, counting up by 1.
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* `case`: A numerical variable indicating cases in the data. A "case"
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indicates an interaction interval and could be defined in different ways.
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Right now a new case begins, when no event occured for 20 seconds.
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* `trace`: A trace is defined as one interaction with one artwork. A trace
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can either start with a `flipCard` event or when an artwork has been
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touched for the first time within this case. A trace ends with the
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artwork card being flipped close again or with the last movement of the
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card within this case. One case can contain several traces with the same
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artwork when the artwork is flipped open and slipped close again several
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times within a short time.
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* `glossar`: An indicator variable with values 0/1 that tracks if a pop-up
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has been opened from the glossar folder. These pop-ups can be assigned to
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the wronge artwork since it is not possible to do this algorithmically.
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It is possible that two artworks are flipped open that could both link to
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the same popup from a glossar. The indicator variable is left as a
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variable, so that these pop-ups can be easily deleted from the data.
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Right now, glossar entries can be ignored completely by setting an
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argument and this is done by default. Using the pop-ups from the glossar
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will need a lot more love, before it behaves satisfactorily.
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* `event`: Indicating the event. Can take tha values `move`, `flipCard`,
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`openTopic`, and `openPopup`.
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* `artwork`: Identifier of the different artworks. This is a 3 digit
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(left-padded) number. See above.
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* `fileId.start` / `fileId.stop`: See above.
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* `date.start` / `date.stop`: See above.
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* `timeMs.start` / `timeMs.stop`: See above.
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* `duration`: Calculated by $timeMs.stop - timeMs.start$ in Milliseconds.
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Needs to be adjusted for events spanning more than one log file by a
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factor of $60,000 \times #logfiles$. See below for details.
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* `topicNumber`: See above.
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* `popup`: See above.
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* `x.start` / `x.stop`: See above.
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* `y.start` / `y.stop`: See above.
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* `distance`: Euclidean distande calculated from $(x.start, y.start)$ and $(x.stop, y.stop)$.
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* `scale.start` / `scale.stop`: See above.
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* `scaleSize`: Relative scaling of artwork card, calculated by
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$\frac{scale.stop}{scale.start}$.
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* `rotation.start` / `rotation.stop`: See above.
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* `rotationDegree`: Difference of rotation from $rotation.stop$ to
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$rotation.start$.
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## How unclosed events are handled
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Events do not necessarily need to be completed. A person can, e.g., leave
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the table and not flip the artwork card close again. For `flipCard`,
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`openTopic`, and `openPopup` the data frame contains `NA` when the event
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does not complete. For `move` events is happens quite often that a start
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event follows a start event and a stop event follows a stop event.
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Technically a move event cannot *not* be finished and the number of events
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without a start or stop indicated that the time resolution was not
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sufficient to catch all these events accurately. Double start and stop
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`move`events have therefore been deleted from the data set.
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<!--
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## How a case is defined
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* Herausfinden, ob mehr als eine Person am Tisch steht?
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@ -108,17 +234,40 @@ files have been affected.
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automatisiert rausziehen? Was ist meine Definition von
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"Interaktionsboost"?
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- Egal wie wir es machen, geht es auf den "Event-Log-Daten"?
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-->
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## Additional meta data
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* Anreicherung der Log-Daten mit weiteren Metadaten? Was wäre interessant?
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For the HAUM data, I added meta data on state holidays and school
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vacations. Additionally, the topic categories of the topic cards were
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extracted from the XML files and added to the data frame.
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This led to the following additional variables:
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* `topicIndex`
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* `topicFile`
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* `topic`
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* `state` (Niedersachsen for complete HAUM data set)
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* `stateCode` (NI)
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* `holiday`
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* `vacations`
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* `stateCodeVacations`
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<!--
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- Metadata on artworks like, name, artist, type of artwork, epoch, etc.
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- School vacations and holidays
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- Special exhibits at the museum
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- Number of visitors per day (bei Sven noch mal nachhaken?)
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- Age structure of visitors per day?
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- ... ????
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-->
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# Problems and how I handled them
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@ -129,10 +278,14 @@ made.
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## Weird behavior of `timeMs` and neg. `duration` values
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I think the negative duration values happen, when an event starts in one
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log file and completes in another one. The variable `timeMs` seems to be
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continuous within one log file but not over several log files.
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`timeMs` resets itself every time a new log file starts. This means that
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the durations of events spanning more than one log file must be adjusted.
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Instead of just calculating $timeMs.stop - timeMs.start$, `timeMs.start`
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must be subtracted from the maximum duration of the log file where the
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event started ($600,000 ms$) and the `timeMs.stop` must be added. If the
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event spans more than two log files, a multiple of $600,000$ must be taken,
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e.g. for three log files it must be: $2 \times 600,000 - timeMs.start +
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timeMs.stop$ and so on.
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```{r, results = FALSE, fig.show = TRUE}
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# Read data
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@ -154,34 +307,22 @@ glossar_dict <- create_glossardict(artworks, glossar_files,
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dat1 <- add_trace(dat, glossar_dict)
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# Close events
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dat2 <- rbind(close_events(dat1, "move"),
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close_events(dat1, "flipCard"),
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close_events(dat1, "openTopic"),
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close_events(dat1, "openPopup"))
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dat2 <- dat2[order(dat2$date.start, dat2$fileId), ]
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dat2 <- rbind(close_events(dat1, "move", rm_nochange_moves = TRUE),
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close_events(dat1, "flipCard", rm_nochange_moves = TRUE),
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close_events(dat1, "openTopic", rm_nochange_moves = TRUE),
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close_events(dat1, "openPopup", rm_nochange_moves = TRUE))
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dat2 <- dat2[order(dat2$fileId.start, dat2$date.start, dat2$timeMs.start), ]
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plot(timeMs ~ as.factor(fileId), dat[1:5000,], xlab = "fileId")
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```
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The boxplot shows that we have a continuous range of values within one log
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file but that `timeMs` does not increase over log files. Since it seems not
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possible to fix this in a consistent way, I set all durations to `NA` where
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`fileId.start` and `fileId.stop` are not identical. I kept `timeMs.start`
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and `timeMs.stop` and also `fileId.start` and `fileId.stop` in the data
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frame, so it is clear why there are no durations. The other
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file but that `timeMs` does not increase over log files. I kept
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`timeMs.start` and `timeMs.stop` and also `fileId.start` and `fileId.stop`
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in the data frame, so it is clear when events span more than one log file.
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NOTE: Part of this problem was that time stamps that are part of the log
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file names are not zero-left-padded and therefore the files were not in the
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correct order when read into R. When zero left padding these file IDs and
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sorting by them and then by `date.start` within, some of the durations are
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exactly fixed. Unfortunately, only three `move` events were fixed, since it
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only fixed irregularities *within* one log file. See below for more
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details.
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UPDATE: By now I remove all events that span more than one log file. This
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lets me improve speed considerably.
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UPDATE: Infos from Philipp:
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<!--
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Infos from Philipp:
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"Bin außerdem gerade den Code von damals durchgegangen. Das Logging läuft
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so: Mit Start der Anwendung wird alle 10 Minuten ein neues Logfile
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@ -194,6 +335,7 @@ nachdem, ob der Tisch zum Zeitpunkt des neuen Logging-Intervalls in
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Benutzung war). Wenn ein Case also über 2+ Logs verteilt ist, musst du auf
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die Duration jeweils 10 Minuten pro Logfile nach dem ersten addieren, damit
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es passt."
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-->
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## Left padding of file IDs
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@ -277,7 +419,7 @@ technical terms that can be opened from the hypertexts on the topic cards.
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Often these information are artwork dependent and then the corresponding
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XML-file is in the folder for this artwork. Sometimes, however, more
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general terms can be opened. In order to avoid multiple files containing
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the same informatione, these were stored in a folder called `glossar` and
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the same information, these were stored in a folder called `glossar` and
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get accessed from there. The raw log files only contain the path to this
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glossar entry and did not record from which artwork it was accessed. I
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tried to assign these glossar entries to the correct artworks. The (very
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@ -310,12 +452,13 @@ pop-ups where another artwork has been opened in between. This is still an
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open TODO to write a more elaborate algorithm.
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All glossar pop-ups that do not get matched with an artwork are removed
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from the data set with a warning.
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from the data set with a warning if the argument `glossar = TRUE` is set.
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Otherwise the glossar entries will be ignored completely.
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## Assign a `case` variable based on "time heuristic"
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One thing needed in order to work with the data set and use it for machine
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learning algorithms like process mining is a variable that tries to
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learning algorithms like process mining, is a variable that tries to
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identify a case. A case variable will structure the data frame in a way
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that navigation behavior can actually be investigated. However, we do not
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know if several people are standing around the table interacting with it or
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@ -329,9 +472,9 @@ gets extracted by the algorithm.
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In order to investigate user behavior on a more fine grained level, it will
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be necessary to come up with a more elaborate approach. A better, still
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simple approach could be to use this kind of time limit and additionally
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simple approach, could be to use this kind of time limit and additionally
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look at the distance between artworks interacted with within one time
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window. When artworks are far apart is seems plausible that more than one
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window. When artworks are far apart it seems plausible that more than one
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person interacted with them. Very short time lapses between events on
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different artworks could also be an indicator that more than one person is
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interacting with the table.
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@ -348,7 +491,7 @@ algorithmic way but only heuristically. I used the `case` variable in order
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to get meaningful units around the artworks.
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If within one case only a single trace for a single artwork was opened, I
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assigned this trace to the moves associated with this artwork. I (quite
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assigned this trace to the moves associated with this artwork. It (quite
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often) happens that within one case one artwork is opened and closed
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several times, each time starting a new trace. I then assigned all the
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following move events to the trace beforehand. This is, of course,
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@ -401,6 +544,16 @@ dim(dat2[is.na(dat2$date.start), ])
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dat2 <- dat2[!is.na(dat2$date.start), ]
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```
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In order to deal with these logging errors, I check the data for what I
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call "fragmented traces". These are traces that cannot happen, when
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everything is logged correctly, e.g., traces containing `flipCard ->
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openPopup` or traces that only consist of `move`, `openTopic`, and
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`openPopup` events. These fragmented traces are removed from the data. It
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was not possible to check them all manually, but the 20 or more that I do
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check in the raw log files were all some kind of logging error like above.
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Most often a card was already closed again, before a topic card or pop-up
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was recorded as being closed.
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## Card indices go from 0 to 7 (instead of 0 to 5 as expected)
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See `questions_number-of-cards.R` for more details.
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@ -411,13 +564,15 @@ displayed on the back of the card. I added an index giving the ordering in
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the index files.
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The possible values in the variable `topicNumber` range from 0 to 7,
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however, not artwork has more than six different numbers. So I just renamed
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however, no artwork has more than six different numbers. So I just renamed
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those numbers from 1 to the highest number, e.g., $0,1,2,4,5,6$ was changed
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to $0\to 1,1\to 2,2\to 3,4\to 4,5\to 5,6\to 6$. Next I used the index to
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assign topics and file names to the according pop-ups. This needs to be
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cross checked with the programming, but seems the most plausible approach
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with my current knowledge.
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<!-- TODO: Ask Philipp -->
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## Extracting topics from `index.xml` vs. `<artwork_number>.xml`
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When I extract the topics from `index.html` I get different topics, than
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@ -479,9 +634,6 @@ It strongly suggests that the artworks haven been updated after the Corona
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pandemic. I think, the table was also moved to a different location at that
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point. (Check with PG to make sure.)
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I need to get the XML files for "504" and "505" from PM in order to extract
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information on them for the metadata.
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# Optimizing resources used by the code
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After I started trying out the functions on the complete data set, it
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@ -492,12 +644,15 @@ frame (at least not on my laptop). The code is supposed to work "out of the
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box" for researchers, hence it *should* run on a regular (8 core) laptop.
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So, I changed the reshaping so that it is done in batches on subsets of the
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data for every `fileId` separately. This means that events that span over
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two raw log files cannot be closed and will then be removed from the data
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set. The functions warns about this, but it is a random process getting rid
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of these data and seems therefore not like a systematic problem. Another
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reason why this is not bad, is that durations cannot be calculated for
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events across log files anyways, because the time stamps do not increase
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systematically over log files (see above).
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two (or more) raw log files cannot be closed and will then be removed from
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the data set. The function warns about this, but it is a random process
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getting rid of these data and seems therefore not like a systematic
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problem. Another reason why this is not bad, is that durations cannot be
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calculated for events across log files anyways, because the time stamps do
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not increase systematically over log files (see above).
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UPDATE: By now, I close the events spanning more than one log file after
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this has been done.
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I meant to put the lists back together with `do.call(rbind, some_list)` but
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this can also not handle big data sets. I therefore switched to
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