Atributes, agregators and their parameters

The attributes (features) describe objects. We distinguish the attributes:

• simple

• complex

  • hierarchical

  • with parameters.

Simple attribute

A simple attribute is an attribute whose value is a simple value, e.g. a number or a literal (a lexical unit representing a fixed numerical or text value, etc.). For a simple attribute, there are no parameters that the user can define when generating the table. Examples of simple attributes are: Active , Surname and First Name , ScopusID.

Complex hierarchical attribute

A complex hierarchical attribute is an attribute whose values build a taxonomy (tree) structure. Hierarchical attributes in the attribute list are marked with a tree icon:

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The terminal value of a hierarchical attribute is the value at the leaf level in the tree.

An example of hierarchical attribute is affiliation. The Affiliation attribute determines the unit of employment of a university employee (at the leaf level). Usually it is one of the faculty units (institute, department, cathedral). As within the hierarchy the higher levels inherit from the lower ones, the staff member affiliated to an institute at a given department is also affiliated at the department. Also, the achievements of the institute are also the achievements of the department. If:

• the structure is a tree in which the path to each leaf is of the same length, e.g. each employee is employed at an institute that is part of a faculty and there are no exceptions to this rule
  and

• the value assigned to an object is a leaf in the tree structure , in this case it is an institute

then you can select such an attribute to show the entire hierarchy of values. This is illustrated in the table below. At the first level there is a department, at the second level there are units subordinated to the departments.

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In reality, the situation is usually different. Not all employees at faculties have to be assigned to the lowest level units - some are affiliated to the higher level (faculty ), others to subordinated institutes and departments, therefore the first row for each faculty may have no title in the Affiliation (2) column (like in the case of the faculty WF above).

If the hierarchy of attribute values is irregular, i.e. the distances to the root are different for different leaves in this hierarchy, it is recommended not to present the table in a hierarchical structure. The alternative in this case is:

1. showing only the highest level of the hierarchy, e.g. department names

2. showing only the lowest values of the hierarchy (leaves), e.g. plant names

3. showing the highest level, and showing the leaves as subordinate values

The way a hierarchical attribute is treated can be determined by clicking the hierarchy icon - tree.

There are three options in the opened window:

1. setting a range for the depth of the tree,

2. selecting only the root level (top level),

3. selecting only the leaf level (lowest).

Selecting the root will give the table with one row for the whole university:

Setting the minimum and maximum values for the Affiliation attribute at level 1 will result in a table with one level for this attribute - these will be departments.

In such a case, the number of people employed at the faculty but not affiliated with the subordinate units will be "included" in the total number of employees of the faculty units.

Complex attribute with parameters

A complex attribute is also an attribute whose value is a set of objects. For example, for the object PERSON, the important attribute is:

• list of publications

• list of implementations describing the project

• list of publications developed as part of the project.

Complex attribute in an attribute list have the word list in their name. An important feature of complex attributes is that in the result table they can only be visualized as:

• set (e.g. by listing the values of target attributes in a cell, i.e. identifiers, names, first and last names)

• using aggregation functions; for example, for the Publication List attribute it may be the cardinality of the set (the number of items in the set) or the sum of points assigned to these publications.

Since objects from a list can have a specific typology, there is often a need to limit the list to a specific type, which is why complex attributes are often equipped with a number of parameters that allow you to limit the set of the list to a certain subset. Restrictions are entered using the gear icon:

The attribute List of publications has parameters, i.e. range of years, type of publication and a marker for omitting achievements not affiliated with the institution.

Let us consider the case when we want to show the publication achievements in a given range of years in the employee table, broken down into specific types of publications. This means that in the case of a complex attribute, you may need to use it to build several columns in a table for:

• journal papers,

• chapters from monographs,

• papers from reviewed conference materials.

For this reason, it is necessary to use aggregation functions several times, separately for journal articles, chapters in monographs, and articles in reviewed conference materials. On the other hand, in each of these columns we would like to have the same limitation of the list of publications to a specific year range. Therefore, the possibility of defining parameters exists on two levels:

1. attribute lists (an arrangement common to all subsequent uses of this attribute)

2. aggregation function (setting specific only to the selected aggregate).

For some (numeric) attributes it is also possible to define ranges. These attributes are also marked with a gear icon, e.g. Age

Other attribute settings

For some attributes, there are two more options that can be used when creating a table:

1.      sort parameter

2.      summary parameter

The setting of both parameters can be changed by clicking on the icons of these parameters.

Sort parameter

The sort parameter provides an ordering of rows or columns, depending on where the attribute is used:

1. ascending – when the arrow points down,

2. descending - when the arrow points up.

Sum parameter

The sum parameter allows you to create a summary row for the parent attributes of the hierarchy. The summary parameter works for hierarchical attributes when at least two levels of hierarchy are generated. An additional condition for this parameter to work is that the Row Summary option is enabled .