Anne Laurent
email: anne.laurent@lirmm.fr

Marie-Jeanne Lesot
email: marie-jeanne.lesot@lip6.fr

Maria Rifqi
email: maria.rifqi@lip6.fr

GRAANK: Exploiting Rank Correlations for Extracting Gradual Itemsets

Keywords: Data Mining, Gradual Dependencies, Gradual Itemsets, Gradual Rules, Ranking Comparison

Gradual dependencies of the form the more A, the more B offer valuable information that linguistically express relationships between variations of the attributes. Several formalisations and automatic extraction algorithms have been proposed recently. In this paper, we first present an overview of these methods. We then propose an algorithm that combines the principles of several existing approaches and benefits from efficient computational properties to extract frequent gradual itemsets.

Introduction

Mining digital data sets is one of the key topics addressed in the field of data mining for extracting rules describing the data, their inner trends and exceptions. In this framework, many kinds of patterns and rules can be mined, leading to various pieces of knowledge delivered to experts. In this respect, association rules and sequential patterns are some of the most frequently used patterns that are often provided to the end-users.

In this paper, we focus on gradual dependencies that convey information in the form of attribute covariations, such as the higher the age, the higher the salary, or, in a biological application domain, the higher the expression of gene G 1 and the lower the expression of gene G 2 , the higher the expression of gene G 3 .

Such dependencies resemble gradual rules that have been studied in the context of fuzzy data, and fuzzy implication, in particular for recommendation and command systems [START_REF] Galichet | Imprecise specification of ill-known functions using gradual rules[END_REF]: they have the same linguistic form, but their semantics are different. Indeed, fuzzy gradual rules [START_REF] Bouchon-Meunier | Fuzzy sets and possibility theory in approximate and plausible reasoning[END_REF] consider the constraints expressed by the rule for each data point individually, requiring that for each point the membership degrees to the modalities involved in the rule satisfy the fuzzy implication, modeled by a residuated implication. Depending on the chosen implication, the gradual rules may include certainty variations, leading to rules such as the later the waking, the more certain the lateness [START_REF] Dubois | Gradual inference rules in approximate reasoning[END_REF].

Gradual dependencies take a different approach and consider tendencies across the whole data set, in terms of correlation of the attribute variations, as will be discussed in more details in Section 2. Two kinds of dependencies can be distinguished: a first class considers linguistic variables represented by fuzzy sets and imposes covariation of the membership degrees across all data [START_REF] Hüllermeier | Association rules for expressing gradual dependencies[END_REF][START_REF] Berzal | An alternative approach to discover gradual dependencies[END_REF]. They are linguistically expressed as, for example, the more the age is "middleaged", the less the number of cars is "low", where "middle-aged" and "low" refer to modalities of the linguistic variables age and number of cars respectively. A second, more recent, category directly considers the numerical values of the attributes and applies to attribute covariation on the whole attribute universe [START_REF] Di Jorio | Fast extraction of gradual association rules: a heuristic based method[END_REF][START_REF] Di Jorio | Mining frequent gradual itemsets from large databases[END_REF]. In some works, the focus has also been put on describing the extent to which the degree increases between objects, especially in the framework of temporal digital data [START_REF] Fiot | Expressing temporal tendencies among quantitative variables using fuzzy sequential patterns[END_REF][START_REF] Fiot | Evolution patterns and gradual trends[END_REF].

The automatic extraction of gradual dependencies has not received much attention even if it is now gaining interest. As for the association rule extraction, the process consists of two steps: first frequent gradual itemsets, or gradual patterns, are extracted; then, causality relations between the items are looked for. In this paper, we focus on the first step, that aims at identifying frequent gradual itemsets.

Existing techniques make use of different frameworks and formalisations, among which statistic linear regression [START_REF] Hüllermeier | Association rules for expressing gradual dependencies[END_REF], or level-wise algorithms relying on generalised definitions of support for gradual itemsets [START_REF] Berzal | An alternative approach to discover gradual dependencies[END_REF][START_REF] Di Jorio | Fast extraction of gradual association rules: a heuristic based method[END_REF][START_REF] Di Jorio | Mining frequent gradual itemsets from large databases[END_REF]. Indeed, level-wise approaches, that evaluate (k + 1)-itemsets knowing the frequent k-itemsets, are very appropriate as the basic property of anti-monotonicity holds when considering gradual patterns: if a gradual pattern containing k attributes (e.g. salary, age) cannot be found in the data set to a sufficient extent, then there is no need to try and find patterns containing these attributes plus other ones. This property allows to design efficient algorithms, as in the case of association rules.

Still the definition of the support of gradual itemsets, i.e. the conditions under which they can be said to occur in the data set, can follow several principles, leading to different definitions and algorithms. In this paper, we first present an overview of the existing approaches, comparing their semantics as well as their properties.

We then show how these approaches can be combined to benefit both from semantic quality and computational efficiency: we follow the definition of gradual dependency based on the notion of order concordance, initially proposed by [START_REF] Berzal | An alternative approach to discover gradual dependencies[END_REF], replacing it in the context of ranking comparison measures. We propose an efficient method, inspired by [START_REF] Di Jorio | Mining frequent gradual itemsets from large databases[END_REF], to compute the corresponding support in a level-wise approach. On one hand the method uses an efficient representation in the form of bitmap matrices, on the other hand, it maintains a concise piece of information that can be queried when navigating from itemsets of one level to the next one. This makes it possible to compute the support without querying the whole data set, which would be both time and memory consuming.

The paper is organized as follows: in Section 2, we recall and compare the main existing approaches allowing users to extract from digital data the hidden gradual patterns. Section 3 introduces our approach called GRAANK (standing for GRAdual rANKing), including definitions and algorithms, while Section 4 concludes and provides the associated perspectives.

State of the art

In this section, after recalling the classic definitions of gradual item, itemset and dependency, as given by [START_REF] Berzal | An alternative approach to discover gradual dependencies[END_REF][START_REF] Di Jorio | Mining frequent gradual itemsets from large databases[END_REF] for instance, we present the various formalisations and algorithms that have been proposed to automatically extract gradual tendencies from data set. We comment them and underline their differences in terms of interpretation and semantics.

Gradual items, gradual itemsets and gradual dependencies

Gradual dependencies extraction applies to a data set D constituted of n objects described by m numerical attributes.

A gradual item is defined as a pair made of an attribute and a variation denoted by ≥ or ≤. If A is an attribute corresponding to the speed of vehicles for instance, A ≥ and A ≤ are gradual items respectively representing (speed, more) and (speed, less). They represent the fact that the attribute values increase (in case of ≥) or decrease (in case of ≤).

A gradual itemset is then defined as a combination of several gradual items, semantically interpreted as their conjunction: for instance M = A ≥ B ≤ is interpreted as the more A and the less B. It imposes a variation constraint on several attributes simultaneously. The number of attributes a gradual itemset involves is called its length.

A gradual dependency in turn, denoted M 1 → M 2 , is defined as a pair of gradual itemsets on which a causality relationship is imposed. It can for instance take the form the faster the speed, then the greater the danger meaning that a speed increase implies a risk increase: it breaks the symmetry of the gradual itemset in which all items play the same role.

Most existing works about gradual itemsets and gradual dependencies [START_REF] Hüllermeier | Association rules for expressing gradual dependencies[END_REF][START_REF] Berzal | An alternative approach to discover gradual dependencies[END_REF] apply to fuzzy data, i.e. data for which the attributes are linguistic variables associated to fuzzy modalities: e.g. a variable representing speed can be associated to 3 modalities, slow, normal, and fast. The data are then described with membership degrees that indicate the extent to which their speeds belong to each modality. A fuzzy gradual item is then a triplet made of an attribute, one of its modalities and a variation, such as (speed, fast, more). It is to be understood as "the faster the speed", or more precisely "the higher the membership degree of the speed to fast". It can be represented in the same formalism as the crisp case, introducing one attribute per modality, creating for instance the attributes speedSlow, speedNormal and speedFast whose values are the membership degrees. The fuzzy gradual item can then be written (speedFast, more).

In the following, we use the notation A ≥ and A ≤ for both crisp and fuzzy data. Moreover, throughout the paper, for any x belonging to the data set D, A(x) denotes the value taken by attribute A for object x.

Approach based on regression

A first interpretation of gradual dependency expresses it as a co-variation constraint [START_REF] Hüllermeier | Association rules for expressing gradual dependencies[END_REF]: Definition 1 (co-variation definition of gradual dependency [START_REF] Hüllermeier | Association rules for expressing gradual dependencies[END_REF]). A gradual dependency such as the more A, the more B holds if an increase in A comes along with an increase in B.

In order to identify such relationships, it is proposed in [START_REF] Hüllermeier | Association rules for expressing gradual dependencies[END_REF] to perform a linear regression analysis between the two attributes. The validity of the gradual tendency is evaluated from the quality of the regression, measured by the normalised mean squared error R 2 , together with the slope of the regression line: attribute pairs that are insufficiently correlated are rejected, as well as pairs for which one attribute remains almost constant while the other one increases, which can be detected by a low slope of the regression line.

This definition and this extraction method apply to pairs of attributes. The extension proposed by [START_REF] Hüllermeier | Association rules for expressing gradual dependencies[END_REF] to longer itemsets considers the case of fuzzy data, for which attributes contain the membership degrees of the data to modalities. It exploits this fuzzy logic framework and the fact that itemsets are interpreted as conjunction of the items they contain: a membership degree to the itemset can be computed using a t-norm, applied to the membership degrees to the items of the considered itemset. The gradual tendency is then understood as a covariance constraint between the aggregated membership degrees. Thus itemsets of length higher than 2 can be handled as itemsets of length 2.

Formulation as an association rule task

Other works take a different point of view and interpret gradual dependencies as constraints imposed to the order induced by the attributes, and not to their numerical values: in [START_REF] Berzal | An alternative approach to discover gradual dependencies[END_REF] gradual dependencies are considered as generalisations of functional dependencies that replace the equality conditions by variation conditions on the values, leading to the following definition: Definition 2 (order-based definition of gradual dependency [START_REF] Berzal | An alternative approach to discover gradual dependencies[END_REF]). A gradual dependency the more A, the more B holds if ∀x,

x ′ ∈ D, A(x) < A(x ′ ) implies B(x) < B(x ′ ).
It must be underlined that this definition takes into account a causality relationship between the itemsets. It states that the ordering induced by attribute A must be identical to that derived from attribute B. In the case of dependencies such as the more A, the less B, the constraint imposes that the orders must be reversed.

In [START_REF] Berzal | An alternative approach to discover gradual dependencies[END_REF] it is proposed to formulate the extraction of such gradual tendencies as the discovery of association rules in a suitable set of transactions obtained from the initial data set D: each pair of objects in the initial data is associated to a transaction in the derived data set D ′ ; items in D ′ are defined as A * ( * ∈ {≥, ≤})

where A are attributes in D. A transaction t in D ′ then possesses an item A * if the pair (x, x ′ ) of D it corresponds to satisfies the constraint imposed by A * , i.e. A(x) * A(x ′ ).

A gradual dependency in D is then equivalent to a classic association rule extracted from D ′ . The support of a gradual itemset is thus defined as the proportion of objects couples that verify the constraints expressed by all the gradual items in the itemset [START_REF] Berzal | An alternative approach to discover gradual dependencies[END_REF]:

supp(A * 1 1 , . . . A * p p ) = 1 |D ′ | |{o = (x, x ′ ) ∈ D ′ /∀j ∈ [1, p] A j (x) * j A j (x ′ )}| (1)
Thus, as the regression approach, this definition also bases the gradual tendencies on correlation between the attributes. However, it considers correlation in terms of the rankings induced by the attributes and not in terms of the values they take. Therefore, it does not rely on any assumption regarding the form of the correlation, e.g. whether it is linear.

Explicitly building the data set D ′ to apply a classic frequent itemset extraction algorithm would have too high a computational cost. The authors propose an approximation method, based on the discretization of the attribute values that requires to keep in memory an array of dimension p k when itemsets of size k are looked for and where p denotes the discretisation level. The computational cost remains high and the experiments are limited to a few attributes.

In an extension [START_REF] Molina | Measuring variation strength in gradual dependencies[END_REF], it is proposed to take into account the variation amplitude between the object couples: instead of setting binary values in D ′ that indicate whether the ordering constraints are satisfied or not, real values are set, depending on the observed values difference: they provide information regarding the extent to which the constraints are satisfied. Fuzzy association rules are then applied to extract information from this data set. This approach bears some similarity to the regression based definition of gradual dependencies that integrates this information through the influence of the regression line slope.

Approach based on conflict sets

On the basis of Definition 2, a different interpretation is proposed in [START_REF] Di Jorio | Fast extraction of gradual association rules: a heuristic based method[END_REF] relying on another definition of support: for an itemset A * 1 1 , . . . , A * p p the support is defined as the maximal number of rows in D, {r 1 , . . . , r l }, for which there exists a permutation π such that ∀j ∈ [1, l-1], ∀k ∈ [1, p], it holds A k (r πj ) * k A k (r πj+1 ): denoting L the set of all such sets of rows, the support is computed as

supp(A * 1 1 , . . . , A * p p ) = 1 |D| max Li∈L |L i | (2)
The authors then propose a heuristic to compute this support for gradual itemsets, in a level-wise process that considers itemsets of increasing lengths. It consists in discarding, at each level, the rows whose so-called conflict set is maximal, i.e. the rows that prevent the maximal number of rows to be sorted. It is a heuristic insofar as it performs local choices: choosing a row with smaller Fig. 1. Two data sets illustrating the influence of deviation amplitude: in both cases, object o2 contradicts the itemset the more A, the more B, also denoted A ≥ B ≥ ; for data set D2, its deviation amplitude is much higher.

conflict set may be suboptimal for a given level but lead to better results at the next level.

It must be underlined that this definition of support gives rise to a major difference with the previous gradual itemsets extraction methods, regarding the data that do not satisfy the itemset: in both the approaches based on regression and on classic association rules, the amplitude of their deviation with the expected behavior is taken into account. This is illustrated on figure 1: in both data sets D 1 and D 2 , the object o 2 prevents the itemset the more A, the more B to be true, but in the second case, the distortion it leads to is much higher. In other terms, it is more an exception than for D 1 .

For the regression based extraction process, this difference is reflected in the regression correlation that is lower for D 2 than for D 1 . In the association rule based approach, o 2 lowers the support of the itemset in D 2 , because it leads to a high number of data pairs that do not satisfy the gradual itemset, namely (o 2 , o 3 ), (o 2 , o 4 ) and (o 2 , o 5 ). In data set D 1 only the pair (o 2 , o 3 ) contradicts the itemset. Therefore for both methods the itemset A ≥ B ≥ has a better score for data set D 1 as for D 2 .

On the contrary, in the conflict set approach, both D 1 and D 2 lead to the same result: in both cases, it is sufficient to delete point o 2 to obtain a perfect ordering of the data. This shows that gradual itemsets can follow different semantics, the choice between them depends on the considered application.

Approach based on the precedence graph

In [START_REF] Di Jorio | Mining frequent gradual itemsets from large databases[END_REF], the authors consider the same definition as the one proposed in the conflict set approach (Eq. ( 2)), and propose a very efficient method based on precedence graphs, named GRITE for GRadual ITemset Extraction: the data are represented through a graph whose nodes are defined as the objects in the data, and the vertices express the precedence relationships derived from the considered itemset. Moreover, the graph is represented by its adjacency matrix, in a bitmap form: for an itemset A * 1 1 , . . . A * p p , the coefficient corresponding to the object pair (x, x ′ ) is 1 if ∀j ∈ [1, p] A j (x) * j A j (x ′ ), 0 otherwise. The support of the considered itemset can then be obtained as the length of the maximal path in the graph.

The relevance of this approach comes from its very high efficiency to generate gradual itemsets of length p + 1 from itemsets of length p: indeed it holds that if s is an itemset generated using s ′ and s ′′ , its matrix M s = M s ′ &M s ′′ where & is the bitwise AND operation.

The proposed GRAANK approach

In this section we propose an algorithm that combines the principles of several existing approaches and benefits from efficient computational properties: we consider the gradual itemset definition used in the association rule formulation [START_REF] Berzal | An alternative approach to discover gradual dependencies[END_REF], see also Section 2.3, and propose an algorithm that exploits the bitmap representation used in the GRITE algorithm [START_REF] Di Jorio | Mining frequent gradual itemsets from large databases[END_REF], see also Section 2.5.

More precisely, we consider the framework of Definition 2 that evaluates gradual tendency in terms of ranking correlation, and the support definition given in Eq. [START_REF] Galichet | Imprecise specification of ill-known functions using gradual rules[END_REF]. We first interpret it in terms of ranking correlation and then describe the approach proposed to compute the support, and present the derived algorithm.

Rank correlation measures

Definition 2 directly relates the gradual dependencies extraction task to the framework of ranking comparison: the problem is to compare the rankings induced by all attributes involved in the itemsets, and to compute their degree of agreement, or of correlation.

The problem of rank correlation has been extensively studied by statisticians, and several measures have been proposed, distinguishing between two ranks and multiple rank comparison. Regarding ranking pairs, the most used measures are the Spearman correlation and the Kendall's tau. The latter is of particular interest for gradual itemsets, as its definition matches Eq. ( 1): given n objects to be ranked, and σ k , k = 1, 2 two rankings where σ k (x) gives the rank of object x in σ k ranking, the Kendall's tau relies on the definition of concordant and discordant pairs: concordant pairs (i, j) are pairs for which the rankings agree, i.e. either σ 1 (i) ≤ σ 1 (j) and σ 2 (i) ≤ σ 2 (j), or σ 1 (i) ≥ σ 1 (j) and σ 2 (i) ≥ σ 2 (j). Non concordant pairs are called discordant pairs. The Kendall's tau is then defined as the proportion of discordant pairs, i.e. the frequency of pair-wise inversions. It is to be noted that the support definition given in Eq. ( 1) equals the proportion of concordant pairs. For multiple rank correlation, the mathematical definitions aim at answering significance tests, so as to determine whether the differences between the rankings are significant. For instance Kendall, together with Babington Smith [START_REF] Kendall | The problem of m rankings[END_REF] proposed the W coefficient: denoting m the number of rankings to be compared, it is based on the observation that in the case of perfect agreement, the set of values taken by the sums of ranks across the rankings for each object is exactly m, 2m, . . . nm. On the contrary, if the rankings are not correlated at all, the rank sums all take the same value, that equals n(n -1)/2m. Therefore, the W coefficient measures the agreement between rankings as the variance of the average rankings for each object. It is normalised by the variance obtained in the ideal case where all rankings are identical. This coefficient is then studied from a statistical point of view, to establish its properties and its distribution, in particular for the definition of significance tests. Moreover equalities between the W coefficient and other approaches to multiple rank correlation, in particular the computation of the average Spearman criterion or the Friedman test, are established, underlining their relationships. Now such criteria, despite their theoretical properties, cannot be applied to gradual itemset quality evaluation because of computational problems: they do not possess monotony properties that would allow to efficiently prune the set of candidate gradual itemsets when going from one level to the next one. More precisely, for a given set of rankings, the addition of a new ranking in the comparison can lead to increase or decrease the W coefficient. This means that even if an itemset is rejected because of a too low W coefficient, it could be necessary to consider longer itemsets containing it, which would lead to too high a computational complexity.

On the contrary, the ranking comparison induced by the support as defined in Eq. ( 1), even if it does not possess statistical properties to perform significance tests, is anti-monotonous: the addition of a new item can only decrease the support value. Thus in the following we measure the multiple ranking agreement as the proportion of data pairs that simultaneously satisfy the constraints imposed by all attributes involved in the considered itemsets.

Support computation

The question then arises how to efficiently compute this quantity. We propose an approach that does not need to perform an approximation as the association rule based method [START_REF] Berzal | An alternative approach to discover gradual dependencies[END_REF]. Following the classic lines, it consists in a level-wise methodology that identifies the relevant gradual itemsets of length k + 1 from those obtained at level k, the relevance being defined as a support value higher than a user-defined threshold.

To illustrate this section, we consider the data set presented in Table 1 that contains information about 4 persons, regarding their age, salary and the number of their granted loans. Table 2 contains the support values, as defined in Eq. ( 1), for several itemsets, as well as the list of concordant data couples for each itemset that justifies the computation of the support.

Itemset List of concordant couples Support

A ≥ S ≥ C A ≥ S ≥ = {(1, 2)(1, 3)(1, 4), (2, 4)} 4/6 A ≥ C ≤ C A ≥ C ≤ = {(1, 2)(1, 4)(2, 4)(3, 2)(3, 4)} 5/6 S ≥ C ≤ C S ≥ C ≤ = {(1, 2)(1, 4)(2, 4)} 3/6 A ≥ S ≥ C ≤ C A ≥ S ≥ C ≤ = {(1, 2)(1, 4)(2, 4)} 3/6
List of concordant couples The support value contains aggregated information as it reduces the set of concordant pairs to its cardinality. It can be observed that it is not possible to compute the support for longer itemsets from shorter ones: from the total numbers of pairs that are concordant for two itemsets of length k, the number of pairs concordant for the joint of these sets cannot be derived. Indeed, one cannot determine whether a given object pair is concordant for both itemsets, or for only one of them, and whether it will remain concordant in the joint itemset. Therefore it is necessary to keep, for any itemset, the list of the object pairs that satisfy all the constraints expressed by the involved items, i.e. the list of concordant pairs. In order to take into account information regarding the sense of variation of the attributes, i.e. to distinguish between A ≤ and A ≥ , we consider object couples instead of pairs, dissociating the two cases of concordance defined in the Kendall's tau: we keep the information whether the couple (i, j) or the couple (j, i) is concordant.

The support then equals the length of the concordant couple list, divided by the total number of object pairs: the latter equals the maximal length of the list, obtained in case of identical rankings. Table 2 contains these lists for the itemsets considered as examples.

List aggregation Keeping such lists of concordance can be compared to the conflict set approach proposed by [START_REF] Di Jorio | Fast extraction of gradual association rules: a heuristic based method[END_REF] (see Section 2.4) in which lists of discordant pairs are handled. The difference is that these lists are considered for each data efficient support computation described in the previous section. More precisely, the algorithm works as follows:

1. Initialization (k = 1): for all attributes A, build the concordance matrices for A ≥ and A ≤ . 2. Candidate gradual itemset generation at level k + 1:

apply the APRIORIgen algorithm to generate candidates from the kitemsets, computing their concordance matrix as the logical AND of the concordance matrices of the joined k-itemsets.

Candidate evaluation:

(a) for all candidate itemsets, compute their support, as the sum of their concordance matrices divided by n(n -1)/2 where n is the number of objects. (b) discard candidates whose support is lower than the user-defined threshold. 4. Iterate on step 2 and 3 until the generation step does not provide any new candidate.

It is to be underlined that this algorithm is very efficient in several aspects: the support computation does not require any counting operation performed on the data set, and can be deduced from information of the previous level. Moreover this information can be handled in an efficient manner too, thanks to the bitwise representation of the concordance matrices.

These advantages are similar to that of the algorithm proposed by [START_REF] Di Jorio | Mining frequent gradual itemsets from large databases[END_REF]. The difference with the latter comes from the candidate evaluation step: the search of the longest path in the matrix is replaced by the simple sum of its components. On one hand, this lowers the computational complexity of the approach. On the other hand, this difference, that appears to be a minor one, actually deeply modifies the semantics of the induced gradual itemsets: it makes it possible to take into account the amplitude of the distortion for data that do not satisfy the gradual itemsets. It offers an alternative interpretation of gradual constraints, whose validity depends on the application and should be evaluated by the user. For the example described in Table 1, the definition of support as longest path leads to a value of 3/4 for the gradual itemset A ≥ S ≥ C ≤ : it is sufficient to suppress one object, p 3 , so that the ordering constraint holds. Using the support definition as length of the concordant couples list, the deviation amplitude is taken into account for this point. Now in this case, p 3 is very young for his high salary, while he has a high number of loans as compared to the other persons, which makes him a very exceptional case. This significantly decreases the gradual itemset support to 1/2. This illustrates the differences between the support definitions.

The proposed approach thus offers an efficient implementation of the support definition proposed by [START_REF] Berzal | An alternative approach to discover gradual dependencies[END_REF], interpreting it in the framework of rank comparison. From a computational point the view, the algorithm benefits from the efficiency of the approach based on binary matrices [START_REF] Di Jorio | Mining frequent gradual itemsets from large databases[END_REF]. Moreover, as the cost of the matrix sum is lower than that of searching the longest path in the precedence graph, even if an efficient algorithm is proposed by [START_REF] Di Jorio | Mining frequent gradual itemsets from large databases[END_REF], its complexity is even lower.

Conclusion

In this paper, we propose an original approach called GRAANK for extracting gradual patterns. This approach integrates complementary paradigms: the definition of gradual itemset support based on rank correlation, the efficiency of level-wise approaches and that of bitmap representation. We provide the necessary formal definitions, together with the associated algorithms.

Beside extensive experimentations including both computation efficiency (time and memory) and semantics (relevance and comparison of the extracted patterns), further works include the study of other optimizations in order to improve the efficiency of our approach. Moreover, we aim at studying how causality links (rules) can be extracted, and how temporality can be handled, for instance to manage databases describing digital records taken by sensors at several time periods. Finally, we aim at studying how our approach, essentially designed to point out the main tendencies from a digital database, can also be considered for pointing out outliers.

Table 1 .

 1 Data set example.

	Name	A: Age	S: Salary	C: Loans
	p1	22	1200	4
	p2	28	1300	3
	p3	24	2200	5
	p4	35	1850	2

Table 2 .

 2 Support and list of concordant couples for some gradual itemsets, computed for the data set described in Table1. To make the table more readable, in the lists of concordant couples, we use the notation (i, j) to denote (pi, pj).

A ≥ S ≥ : 1 2 3 4 1 -1 1 1 2 0 -0 1 3 0 0 -0 4 0 0 0 -A ≥ C ≤ : 1 2 3 4 1 -1 0 1 2 0 -0 1 3 0 1 -1 4 0 0 0 -S ≥ C ≤ : 1 2 3 4 1 -1 0 1 2 0 -0 1 3 0 0 -0 4 0 0 0 -

1 2 3 4 1 -1 0 1 2 0 -0 1 3 0 0 -0 4 0 0 0 -Fig. 2. Binary matrices representing the sets of concordant object pairs for some gradual itemsets, computed for the data set described in Table 1.

point in [START_REF] Di Jorio | Fast extraction of gradual association rules: a heuristic based method[END_REF], whereas we propose to attach them to itemsets. The interest of such higher level concordant lists is that they provide an efficient and exact method to generalise gradual itemsets of length k to itemsets of length k + 1.

Indeed, the list of concordant couples for a gradual itemset s generated using two gradual itemsets s ′ and s ′′ is obtained as the intersection of their lists, as illustrated in Table 2 for the considered example.

Formally as s is generated from s ′ and s ′′ , it only differs from s ′ by one item that belongs to s ′′ (and reciprocally):without loss of generality if

. Thus an object couple that satisfies all gradual items A * j j , B and C contained in s ′ and s ′′ , also satisfies all items in s; reciprocally, if it satisfies all items in s, it satisfies all items contained in s ′ and s ′′ .

Bitwise representation

The problem is then to design an efficient method to store and handle the lists of concordant couples. To that aim, we propose to exploit a bitwise representation as used by [START_REF] Di Jorio | Mining frequent gradual itemsets from large databases[END_REF]: it consists in defining a matrix for each considered itemset, that indicates for each couple of data, whether it is concordant or not: for an itemset A * 1 1 , . . . A * k p , the value corresponding to the object couple (x, y) is 1 if ∀j ∈ [1, k] A j (x) * j A j (y), 0 otherwise. These matrices are illustrated on Figure 2 for the considered example.

On one hand, this representation makes it very easy to go from itemsets of length k to itemsets of length k + 1: the intersection of the concordance lists equals the bitwise AND operation between the corresponding matrices. On the other hand, the support of the itemset is simply obtained as the sum of the elements of the matrix, divided by the total number of pairs of objects.

The GRAANK algorithm

The proposed algorithm thus follows the principle of the APRIORI algorithm, modifying the step of candidate itemset evaluation that is performed using the


Curator Nadine Atallah

Nour Abdel-Baky

Helena Duncan Macdonald

Duncan Macdonald

Brenda Segone

Helena Abdelnasser

Jomana El Soufani

Dina Jereidini

Noor Ibrahim

Mona Marzouk

Nevine Henein

Aya Tarek, 2019, series of sketches on graphic tablet, part of the research process for a large scale painting It is my honor to introduce this exhibition of painters who are expanding upon the realms of possibility afforded by their medium within Egypt and beyond. MASR Research in Modern and Contemporary Art's mission is to create artistic research that allows academics, artists, students, and the public to analyze and critically engage with discursive issues in modern and contemporary art in Egyptian society. We are equally committed to producing professional art exhibitions, artist talks, interviews, workshops, curated events, small-scale publications, and in turn, delivering art-centered education.

Annually, we produce two professional exhibitions at the Sharjah Art Gallery, in addition to these associated events. As part of our work, we endeavor to pose a number of critical questions, among them: How can art scenes in Egypt be nurtured? And how can artists be part of a larger sustainable eco-system of artistic creation? The painters in this show are contributing much to the landscape of art creation here. Together with Brenda Segone, co-project investigator of MASR, we explore these issues through the creation and presentation of research that dovetails with art education coursework in Visual Arts.

For our second exhibition, In Conversation. A Painting Show, we have had the good fortune of working with guest curator Nadine Atallah. Ms. Atallah has brought together a diverse group of artists who are fully aware of the legacy of painting in this country and choose to expand upon these legacies in an array of trajectories. Their work reaffirms that painting is alive and well in Egypt, despite the fact that the contemporary art world tends to downplay its value with an impossible search for constant newness.

In this exhibition, you will find tapestry mixed with painting, film deconstruction and reconstruction through paint and stop motion, the questioning of photographic truth, the representation of aesthetics and politics in street art, and much more. This show is a wonderful example of how art inevitably coaxes the viewer into imagining a range of possible new worlds, each as complex and unique as the artist who created them.

Introduction

Abdelnasser, and Jomana El Soufani, for their efforts. Dina Jereidini did an immense amount of coordinating and planning to make this show possible. The technical support team from the Sharjah Art Gallery also deserve thanks for their diligent work to produce this wonderful exhibition. Thanks to Noor Ibrahim for her design work for all materials related to the project. Thanks to the administrative staff in the Department of the Arts for their assistance. Lastly, this research would not have been possible without financial support from AUC in the form of a multi-year research grant.

Brenda Segone Writer, Researcher Visual Arts Program, AUC

In line with MASR's attempt to map the diversity of the modern and contemporary art scene in Egypt, for our second edition 1 we invited an external curator, Nadine Atallah, an art historian who is also one of the founding members of Madrassa Collective, a transnational curatorial platform, to imagine an exhibition under the thematic of "Mapping discourses and issues in contemporary art. How is it reflected currently in the media?" While this exhibition did not follow a typical methodology and was developed gradually based on the incursions made by Nadine Atallah into the Egyptian art scene, it nevertheless followed a guiding principle, even if an unusual one: the desire to do something in a different way. We leave it to the public to discover how our methodology was indeed different. All the parties involved had as a common motivation the desire to produce, to make art speak, and to speak through art. This says a lot about the vitality of the art scene in Egypt.

The usual discrepancy between artistic practices and curatorial statements of funded projects that oblige one to be inscribed in a certain geopolitical perspective is irrelevant here. There is no attempt to forcibly glue the creative processes with certain discourses in order to fit a certain brief. In this regard, In Conversation. A Painting Show goes against the discourses one finds around art exhibits by muting them. It gives way to artists and to their creative process with the medium of painting and its hybrid forms as an anchor. The different choices made throughout the development of the project will undoubtedly raise many questions around the current exhibition. It is precisely in the questions themselves, that some answers can be found.

The preparation of this exhibition, within the AUC framework, took place largely on the Internet, but also through a few face-to-face meetings. The exchange of e-mails, in itself a form of contemporary conversation, and the most common in the world of contemporary art, if not the exclusive form, raises questions about the artist as an 1 Our first exhibition was Concrete Poetry in Space, a solo show by Hazem El Mestikawy, Fall 2018, AUC.

individual and the Internet as a structure. There were indeed plenty of conversations! At times short, at times long, at times passionate, or complacent, at shorter or longer intervals, sometimes offset, the whole gamut was there. Needless to say, that with a conversation, comes the interval of reflection until the next conversation, and so on, to the point where everything gets transferred to the audience. I would like to sincerely thank Nadine Atallah for her immense engagement with and enthusiasm for the project. I would also like to thank the artists and all the collaborators of the MASR team!

Foreword In Conversation. A Painting Show

Conversation: A Tradition in the History of Painting Paintings do not explain themselves; they require interpretation and imagination. This is one of the preliminary statements of In Conversation. A Painting Show. Discussion with practicing artists is an essential starting point to understanding the conceptual processes shaping their work, and the visual and plastic codes at play. In art history, there has been a tradition of conversation with painters since the Renaissance, in line with the writings of Alberti, Félibien, and more recently, Isabelle Graw who even states that there is "no theory of painting without conversation." 1 Even if it does not take the form of interviews, the seminal book on Egyptian modern art by Aimé Azar, La Peinture moderne en Égypte, 2 also derives from studio visits and exchanges with the artists.

Conversations operate as a driving force for observation and insight, but they certainly are not a reader's guide to an artist's work: language is the tool of art historians, critics, and even to a certain extent, of curators; it is not the tool of painters. Therefore, this exhibition is not an attempt to define a theme, a category, or a label which would supposedly reveal an intrinsic likeness of the exhibited artworks, or worse, a purported essence of contemporary painting in Egypt. Rather, this "Painting Show" stems from empirical observation and from conversations with artists, fellow researchers, and curators. It owes a lot to these exchanges in its attempt to elucidate some painting practices taking place in Egypt today. At the same time, this exhibition aims to stimulate further conversations between different artists who all have a reflexive approach to the medium of painting; especially as most of them were unfamiliar with each other's work before the exhibition. The reality of contemporary painting in Egypt, and more broadly of contemporary creation, involves ramified artistic communities and individuals, which may or may not interconnect. This multiplicity of art worlds is shaped by the artists' diversity of training and life paths: Institutional education at the Fine Art School of Cairo and its counterparts in Alexandria, Minya, and Luxor or at the Higher Institute of Art Education; non-academic studies; residencies and projects in countries such as Japan, Germany, and Brazil; and migration, both from and to Egypt. Even if the local scene is often self-declared as a "small" one, its complexity should be acknowledged.

Historicizing Painting in Egypt: Starting Assumptions

One of the motivations for the conversations behind this exhibition was to place Egyptian reality in confrontation with the global obsession with the end of painting.

Starting in the 1980s, numerous exhibitions and publications in the West have pointed to a crisis in painting, leading to reflections on its "post-medium condition". 3 The past few years have seen a revival of painting on the global scale, but for a long time, some have posited that photography irrevocably wiped out painting as a means of representation, or have asserted its obsolescence in a world increasingly affected by the proliferation of images. Others have cited the breach created by minimalism and conceptual art in reaction to the cumbersome past of the most traditionally revered medium of fine art. But painting, as it has been practiced in Europe for centuries, is a much more recent tradition in Egypt. While it doesn't share the same historical burden, it does carry another heavy weight, that of colonialism and its reverberations. Indeed, painting, as a fine art tradition, was introduced to Egypt in the 19th century by European Orientalist painters.4 Some of them became the first professors at the Faculty of Fine Arts founded in Cairo in 1908, contributing to the medium's institutionalization. This means that, effectively, fine art painting developed concomitantly with photography in Egypt, which was introduced in the 1860s by European amateurs and professionals who produced touristic views of Cairo for the eyes of foreign audiences. 5 One can assume that such a chronological coincidence involved major differences in the ontology of painting in Egypt in comparison with the West. No comprehensive study has examined this phenomenon yet, however, it would certainly seem that painting and photography evolved side by side, as nonrival correlative practices. Many modern painters in Egypt used to paint based on photographs, and some of them even produced their own photographs as models for their compositions.6 This is a widespread practice all around the globe, but the essential difference is that fine art painting has no pre-photographic existence in Egypt.

Thereby, in the Egyptian context, painting could have developed as a nonrepresentational medium from the outset, because the alternative of photography was always there -regardless of the technical and financial criteria at stake. Yet, interestingly enough, this isn't what happened: the academic teaching methods of those first European professors still prevail in the painting departments of the Egyptian faculties of fine arts today. Fruit baskets and ceramic pitchers are arranged on pedestals dramatically wrapped in colorful pieces of fabric for groups of students painstakingly endeavoring to copy the installation. While most art schools in Europe and the US emphasize theoretical and critical thinking over drawing skills, the fact that still-life classes continue in Egypt suggests that there's never been any urge to revolt against or even to challenge the necessity of representation, and through it, of painting. The fine art tradition has been adopted even though its history wasn't inherited. Incidentally, it is meaningful that no specific terms accurately and specifically designating the painted image or painting as a medium were ever coined in the Arabic language. Tasweer and surah refer to all kinds of images, whether painted, photographic, material, or digital; al-fann al-rasm literally means "the art of drawing"; lawn means first and foremost simply "color"; and lawha can refer to any regular wooden panel as well as to a painted work of art. This shortcoming in the art vocabulary implies an intermingling of the concepts of painting and imagery while suggesting the supremacy of depiction over the plastic specificities of the medium. In fact, the intricate relationship between the emergence of modern art and the establishment of the modern Egyptian nation-state may have played a role in encouraging figurative painting over abstraction. Since the beginning of the 20th century, and more obviously during the Nasser era, the development of political representations based on an identifiable iconography, has been encouraged by competitions and state commissions to fulfil the need for a national imagery capable of sustaining a major political project: independence from colonial rule.7 Yet, it should be stressed that figurative painting at the time was rarely naturalistic, or even realistic: although it usually related to the real world, it did not pretend to illusion.8

Intermediality as the Future of Painting?

Representation methods and painting themes have evolved since then: the sociopolitical concerns at the core of modern painting have given way to more intimate explorations of the self and the human psyche. In fact, it appears that contemporary painting is scarcely informed by the styles and issues of Egyptian modern painting.

Indeed, the new generations usually know little about the work of their predecessors, as it is usually not part of their art education. The dearth of information about cultural initiatives, as well as the difficulty in accessing some collections, do not help young artists assimilate the history of Egyptian painting. As a matter of fact, the practice of contemporary Egyptian painters seems generally more impacted by the advent of new media and their normalization since the 1990s than by a sense of belonging to a national visual culture. Incidentally, the notion of contemporary art is usually associated with new media, such as video, installation, performance, or digital arts. Even though it still is widely exercised, painting is often accused of being too academic and decried as purely decorative. Within the Arab world, however, it is undoubtedly the medium favored by collectors, and as such, galleries enthusiastically support its production. The challenge, therefore, is for painting to find a way to assert itself as a contemporary practice. It is not a matter of renegotiating the necessity of painting today; this has been demonstrated as a non-relevant issue in Egypt. Rather, the question that arises is whether the digital era is arousing the revolution in the status and the essence of painting which photography didn't provoke.The ability of painting to be reinvented as the confluence of photography, cinema, Internet imagery, manual, industrial, and digital processes implies deep transformations in the ways a picture is conceived, sketched, and realized. The painters introduced in this exhibition may all have their own poetics and plastic languages; however, they all share a selfreflective and introspective relation to images, stemming from the combined force of new media, postmodern thought, and painting history. Aya Tarek's large-scale painting hanging on the building's façade opens the exhibition. The usual banner has been replaced by an original artwork, both as a celebration of pictorial matter over printed image, and a nod to the bygone tradition of painted posters, in particular, those of the Egyptian movie industry. Originally a street painter, Tarek produces work that is usually site specific, spreading out over buildings and interacting with urban landscapes. The impossibility of continuing this practice in the streets of Egypt implies a reconfiguration of her processes and even of the status of her work, impacting the paintings' temporality of production and lifetime. For In Conversation. A Painting Show, Tarek has explored the ancient myth of the origin of painting as told by Pliny in his Natural History: A young woman from Corinth draws in outline on the wall the shadow of her lover's face, before he leaves for travels abroad.

While pointing to the fact that mural painting preceded the medium's assimilation as a fine art, Pliny's story also suggests that the history of painting began with a woman, and more precisely with female desire. The eroticism underlying the painter's look and gesture are captured in Tarek's carnal sketches. These sketches, which show a research in progress, are produced with a graphic tablet and are meant to take shape and flesh only in the final painting. Hend Samir's paintings saturate the wandering eye with accumulated details, like off-the-wall materializations of media hype. She, too, reuses figures taken from her personal photo albums, but she mixes them with pictures found on the Internet and in magazines, fusing intimate scenes with advertising. Samir explains that she conceives her compositions as collages that juxtapose elements in some kind of aesthetical relativism. The main protagonists are children, usually lined up as if for a class photo. Yet, while seated, they actively engage in daily life activities or surreal games (Rhythm of a Little Piano Player, 2016), struggle with nightmares, or stroll in adventurous dreams (Night Critters, 2019). The figures' boundless energy is conveyed by hazy backgrounds which do not frame a setting but structure the compositions either with large brushstrokes (Future Seeds, 2017) or a harmonious palette (Little Musicians in the Never Land, 2018). The panoramic format of some of the pieces enhances their narrative dimension. The compositions' balance is emphasized in the black and white paintings and stems from vivid contrasts in some instances (Dinner in Bed, 2018).

Lina

Rania Fouad has been working on a project titled Parallel Architectures since 2015.

Both modest and concurrently ambitious, the work in progress is conceived as an entirely hand-painted animated film made using the rotoscoping process. The sequences exhibited here are extracted from Pina Bausch's The Plaint of the Empress (1989), Godfrey Reggio's Kyoyaanisqatsi (1982), and Mona Hatoum's Changing Parts (1984). Through painting, frame by frame, Fouad tries to capture the infinitesimal instant which separates, or-conversely-connects, two moving images. This way, she deconstructs the film extracts and gives them a material flesh, fixed in silent immobility. Each sequence lasts only a few seconds and is the result of more than a hundred painstaking frames, made of layers of oil painting over a photographic image. This extremely slow manual work contrasts with the cinematic speed. Breaking down the movement sometimes leads to the abstraction of the represented image. This is particularly apparent in a scene of explosion taken from Kyoyaanisqatsi. Similarly, in the sequence from The Plaint of the Empress, the series of geometric shapes modelled in a bluish grey palette, reveal the graceful body of a draped dancer only when animated. The frames play with various scroll speeds and are filmed in 16 mm or digital video. Particular attention is paid to the paintings' textures and skins, as Fouad tries to convey their haptic properties. Mona Marzouk's Bark series (2018) uses a minimalist aesthetic to address virtual reality. With the simple image of a tree trunk, Marzouk imagines a history of technology: a robotic hand lights a fire by rubbing a stick against a log, referring to one of humanity's primary acquired technical skills. A symbol of human beings' fundamental interactions with nature, the trunk also stands as the antithesis of virtual reality as disembodied experience. It also reminds of environmental issues previously addressed in The Bride Stripped Bare by her Energy's Evil (2008). Over the various paintings, the tree trunk becomes in turn a museum object, a subject of laboratory tests, and a projected image on a screen; sometimes it looks somewhat anthropomorphic or animal, and other times, it is just inert. The compositions seek to provide a three-dimensional impression and the vibrant colors suggest the hypnotic attractiveness of screens while echoing the aesthetic of the first videogames. Marzouk makes her sketches from images collected on the Internet and assembled using digital editing. Using manual processes, she then traces the outlines on the canvas to give form to the pictorial image.

Noor Abuarafeh provides a counterpoint to the history of painting in Egypt with her video Observational Desire on a Memory that Remains (2014) by evoking the case of modern painting in Palestine. Abuarafeh is not a painter, and her presence in this "Painting Show" may seem odd. Yet, in addition to advancing the intermedial dialogue, her video creates a link between two fundamental issues addressed here: the legacy of modern painting for new generations of artists and the reflections on paintings as both objects and images. The video tells the story of fourteen Palestinian painters, all male, who participated in an exhibition in 1985 and were captured together for posterity in a group photograph. The photo soon turns out to be a hyper-realistic painting printed in China as part of a project by artist Khalil Rabah; and from the outset, the image's ambiguous status casts a doubt on the veracity of the facts uncovered by Abuarafeh.

The artist investigated to try to find out what had become of these painters, focusing on one of them in particular. The narrative, which emphasizes the artist's research journey, reveals the complexity and discontinuity of the relationship between two generations of artists developing in fundamentally different societies and art worlds. Some paintings are re-enacted as living tableaux: paradoxically, this physical embodiment, instead of maintaining the painting's materiality, makes it dissolve into the digital video recording. Thus, the persistence of paintings both as images -in the memory of those who have seen them -and as objects -found, hidden, forgotten, or lost -is questioned. But the only image which could never be re-enacted is the one representing the group of painters: Abuarafeh's attempt to gather them all again failed due to mobility restrictions and death. More recently, the artist found out that a woman took part in this 1985 painting show, although she does not appear in the photograph. She has started an ongoing research to discover who this woman was.

Acknowldegments: I wish to warmly thank the team of the AUC and the MASR project, and especially Brenda Segone who kindly invited me to curate this exhibition and followed each step of its preparation, as well as Duncan McDonald and Dina Jereidini for their valuable help and enthusiastic support. Deep thanks to the many protagonists of the conversations directly or indirectly behind this exhibition, and in particular to Doa Aly, Ghalia Elsrakbi, Victor Guégan, Samir El-Kordy, Ash Moniz, and Bassem Yousri, and to all the artists who kindly opened the doors of their studios to me. My gratitude also goes to Aleya Hamza and Sara El-Adl from Gypsum Gallery, as well as to Lina Mowafy and the Arts-Mart team for their kind collaboration.

Last but not least, many thanks to Aya, Hend, Lina, Mona, Nada, Noor, and Homo sapiens, you have got to organize, categorize, trim -cut -clip and define everything that has ever been and ever will be so it can be digested by your mortal beings. We are the Y2k at the beginning of the millennium. We are Mathew

McConaughey in a black hole portal trying to control the gravity of the past, but we can barely be felt. We are off your grid and we fit in endless dimensions where we can exist; where you are not the norm and we are not forced to conform."

Born

NADA ELKALAAWY

"I see a mass of white. A bride, a groom, a young lady grinning like a Cheshire cat or an eccedentesiast. I then see a shadow that depicts a candle, on top of an overflowing tablecloth. The white leads me to the bottom right corner of the image. There is an accidental shadow that extends beyond the frame. It could be the hand of the photographer. It could also be a ghost. The ghost is something that is lost, or barely visible, something that is seemingly not there to our eyes but then makes itself known. I feel like the language of photography often leaves us with paradoxes. There is something passive about the notion of looking but nothing about photography is passive, since the act of taking a photograph itself is a conscious action. I skip the man about to wipe his glasses, the woman staring

Mass of White

right at the camera, and spot the velvet magenta coat. She stands out, possibly because her coat is one of the few non-sepia-toned elements. I start wondering if it is by coincidence or if she is someone of significance, a guest of honor perhaps.

Behind her sits an old man wearing a striped suit. Assuming he is well hidden behind the crowd, he decides to snooze, unaware that his image is being captured. I go back to the starting point where the bride and groom stand and my eyes hover for a bit before they are dragged to the next white item on the left. I pause and start thinking about the nature of the medium and how deceptive and misleading it can be. The timing of the shutter click and the angle the photo is taken from can give an impression that differs from reality.

Above, at the back, are two men acting like they do not belong to the gathering. I say that because of how they are dressed and the way they look at the others. The only thing they all have in common is that they are in the same place at the same time but the rest of the party fails to notice them. There is a having-been-there quality that acts as proof to the existence of a specific thing in a specific place at a specific time. The degree to which a photo reveals its meaning, message, and the photographer's decisions is variable. The 'studium' and 'punctum' as described by philosopher Roland Barthes make those decisions clearer for us. The 'studium' is the overall scene represented in an image. In this case, it is a wedding of a middle to upper class family in the 1970s. The 'punctum' represents all those instant, small, and unexpected details I have mentioned, the ones that initially lured me to this I rely on moving images as a form of transformation. The uncertainty of seeing, and the everlasting shift from one still to another, make tangible the 'in-between'. The 'in-between' is a spatial concept, but also a time interval that generates rhythm and simultaneous awareness of the pause between two structural parts. In Japan, it is called Ma/ , or the space between two things. It is not considered as an absence that separates, but as a relationship. Not the absence of something, but the heart of things. The interval which shapes the whole. Ma provokes the eye to scan the screen for nuances of the unseen, shifts attention to the spectator's eye, to the fleeting ghosts that take refuge in the ma (giving them shapes, forms, colors, and textures). For this exhibition, I worked on two new sequences; mostly 'people-less' shots in which the absence or the hardly perceptible presence of human figures was replaced by tracking space or (an exploding) landscape. Both sequences act, within the context of the original film, as psychological doors to the otherness of the self, as mirrors, or media to express hypothetical inner spaces of various women."

  Osama's works provide a sense of continuity between the tradition of fine art and contemporary painting practices. Although Osama has taken part in the Salzburg Summer Academy founded in Vienna by the expressionist painter Oskar Kokoschka, her work is more informed by a thorough knowledge of the various ages of Egyptian art history rather than by European expressionism. She has studied Egyptology and is also familiar with the oasis cultures. Fed by these references, she elaborates a personal mythology. The Girl Screaming at a Cow's Head (2008) and Girl Screaming at a Skull (2008) depict exaggeratedly anxious women struggling with an archaic symbolism. The artist explains that a cinema workshop at Cairo's Jesuit school in 2007 made her more aware of composition and lighting issues, while enhancing her capacity to express drama through body language. My Living Units (2017) shows the evolution of the artist's work towards a more intimate and more intricate iconography.Nada Elkalaawy grew up between Egyptian and British cultures. Her personal history is also her primary work material. She uses the photo albums of three generations of her family to dream up an ideal world, while experimenting with ways of shaping memories which are not always hers. Her compositions combine elements taken from several photographs, intertwining multiple temporalities and localities with purely imaginary details. In her small-scale paintings, she experiments with various techniques including transfer (The Girl inWhite, 2018). Her relationship to time does not only express itself through nostalgia, but also through sophisticated production processes, such as the patiently handwoven tapestries in Summer Blues (2019). The Queen of the Night (2019) is originally a painting on glass inspired by a photograph and converted into a digital file to produce a jacquard tapestry using a computerized loom. The immediacy of the mechanical production is offset by the initial painting work and by dainty finishing touches such as hand-embroidered details. The tapestry depicts young girls on a stage, dressed as 'arayis el-mouled, typical sugar dolls sold to celebrate the birth of the Prophet. The dark blue sky expands in a mural painting evocative of Karl Friedrich Schinkel's set design inspired by Egyptian style for Mozart's Magic Flute, which gives the piece its name.

  Rania who provided, through their work and our exchanges, great insights on what painting is to them. 2019, series of sketches on graphic tablet, part of the research process for a large scale painting AYA TAREK "A supernova is the closest to what we call home.

  in Alexandria, Egypt in 1989, Aya Tarek is a painter, street artist, and illustrator with an exciting portfolio of diverse art projects, feature films, and art collaborations in countries ranging from Brazil to Germany. Her work explores the different interchanges within modes of urban communication and the dynamic of a public space. Using a vibrant, comic-derived aesthetic, and often working through site-specific murals, she aims to trigger a humorous sense of controversy, investigating different ideas pertaining to the different public contexts. Tarek has showcased her artwork in various exhibitions and events around the world, including Omar A Sharif Mural, Antigel Festival, Geneva (2018); Sprezzatura, SOMA Art, Cairo (2018); Aya in America, Portland (2017); Paper Trail, Gypsum Gallery, Cairo (2017); Objects in the Mirror Are Closer than They Appear, SOMA Art, Cairo (2017); Afreaka Festival, Sao Paulo (2016); World Premiere of a New Mural by Aya Tarek, USF Contemporary Art Museum, Florida (2015); Urban Art Biennale, Weltkulturerbe Völklinger Hütte, Völklingen (2015); Djerbahood, Itinerrance Gallery, Djerba (2014); Vagabonds Congress, Theatre RMPH, Stuttgart (2014); Cityleaks, Cologne (2013); White Walls, Beirut Art Centre, Beirut (2012); Arabic Graffiti & Egyptian Street Art in Frankfurt, Frankfurt (2012); Ankh Project, ITP Berlin (2011); Graffiti: Style/ History/ Experience, Goethe Institute, Alexandria (2011); Bytes and Pieces, Sharjah Art Foundation, Sharjah (2011); Shopping Malls, Alexandria Contemporary Art Forum, Alexandria (2010); PICK 4, Townhouse Gallery, Cairo (2009). She is also a recipient of several residencies, including Dakakin, Alriwaq Contemporary Art Space, Bahrain and Artist in Resident Show, Arnaldo Pomodoro Foundation, Italy. In 2015 and 2016, she worked with master printer Tim Baker on photogravure at the University of South Florida's Graphic Studio. 2019, series of sketches on graphic tablet, research in progress for a large scale painting LINA OSAMA Born in Cairo in 1986, Lina Osama is a multidisciplinary visual artist. She holds a bachelor's degree in painting from Helwan University's Faculty of Fine Arts, Cairo, 2009 and has won scholarships at Salzburg and Traunkirchen Fine Arts Academies in Austria in 2006, 2008, 2009, as well as residencies to Siwa Oasis in 2009 and 2018. She won a painting prize at the Cairo Youth Salon in 2007 and the first prize in painting at the Young Artist Salon in 2015. She has participated in more than 70 exhibitions since 1999 in Egypt, Austria, France, Italy, Romania, and Morocco. These include Art Times, Picasso Art Gallery, Cairo (2018); Agenda, Bibliotheca Alexandrina, Alexandria (2018); Humans, Made in. Art Gallery, Italy (2016); Printemps du Nil, Paris (2011); Port Said Biennale, Port Said (2009); a group exhibition at Gmundten 422, Austria (2008); and the Cairo Youth Salon, editions 14, 18, 21, 25, 26, and 27. In addition, she has also had solo shows at the Cairo Atelier (2010); the Austrian Cultural Forum in Cairo (2015); and Heliopolis University for Sustainable Development (2017). She is also the founder and curator of Living Units exhibitions at the Goethe Institut, Nile Art, and the Gezira Art Center in Cairo; the Egyptian Cultural Office in Vienna; and Go Arts in Bucharest 2016-2018. Osama has official and private collectibles in Egypt, USA, France, Morocco, and Austria. My Living Units, 2017, mixed media on canvas, 250 x 145 cm Girl Screaming at a Cow's Head, 2008, oil on canvas, 120 x 160 cm Girl Screaming at a Skull, 2008, oil on canvas, 100 x 150 cm Family Photograph, 1980s, Alexandria

"

  photograph."

I

  wonder if I can create my own kind of synesthesia that spans across various media An ongoing film project based on moving color sequences. Units within a greater time organism being gradually constructed. Introduction to Parallel Architectures as a non-verbal register of perception. One that transgresses the boundaries and expands the parameters of painting by putting it in dialogue with time-based visual media, injecting time into painting by cinematic means to celebrate haptic visuality/ the tactility of moving image. This 'requires the viewer to contemplate the image as a material presence rather than an easily identifiable representational cog in a narrative wheel' 1 Parallel Architectures is still in progress. Along its laborious phases of production, sequences were shown within the following venues: Gypsum Gallery, Cairo (2016); the Centre for Creative Activities, Ustka (2016); the Faculty of Fine Arts, Cairo (2016-2018); Bibliotheca Alexandrina, Alexandria (2016); Contemporary Image Collective (CIC), Cairo (2017).

1

  Graw Isabelle, The Love of Painting. Genealogy of a Success Medium, Sternberg Press, Berlin, 2018, p. 18. 2 Azar Aimé, La Peinture moderne en Égypte, Les Éditions Nouvelles, Le Caire, 1961.

See for instance: Harris, Jonathan, editor. Critical Perspectives on Contemporary Painting. Hybridity, Hegemony, Historicism, Liverpool University Press, 2003; de Chassey, Éric. Après la fin, Collection Les Mondes de l'art. Klincksieck. 2017; "Renouveau de la peinture." Ligeia 2006/1, n°65-68, 2006; Hoptman, Laura, editor. The Forever Now: Contemporary Painting in an Atemporal World. The Museum of Modern Art, 2014; Hochdorfe, Achim, et al. Painting 2.0. Expression in the Information Age, Prestel, 2015.

4 For further information on the introduction of fine arts in Egypt, see: Radwan, Nadia. Les modernes d'Égypte, Peter Lang, 2017

. 5 For further information on the beginnings of photography in Egypt, see: Collective Le Caire dessiné et photographié au XIXe siècle, Collection D'une rive l'autre. Picard, 2013.

This practice is documented, among others, in the personal documentation and photographs of artist Margo Veillon kept at AUC's Rare Books and Special Collections Library.

For instance, representations of fellahin busy in the fields, of workers and popular neighbourhoods, or of Aswan's high dam, are some of the subjects typical of the iconography of the 1950s and 1960s.

Those who are not familiar with Egyptian modern art can observe the paintings by Gazbia Sirry displayed in the administrative building of AUC's new campus. Not only did Gazbia Sirry experiment with various modes of figuration, but she also shifted to a more abstract painting style from the late 1960s. Examples of geometric landscapes from the AUC's collection suggest that abstraction, as she practiced it, was not a complete rejection of representation, but rather a way to engage in new plastic researches.

Totaro, Donato,

2002, Deleuzian Film Analysis: The Skin of the Film, vol. 6, issue 6. Online: http://offscreen.com/ view/skin_of_film

Aya Tarek, 2019, series of sketches on graphic tablet, part of the research process for a large scale painting

Parallel Architectures, 2018, oil painting on photograph, frames from a sequence based on film archive Parallel Architectures, 2018, oil painting on photograph, frames from a sequence based on film archive Parallel Architectures, 2018, oil painting on photograph, frames from a sequence based on film archive

project led by faculty in the Visual Arts that aims at exploring and documenting critical issues within the Egyptian art fabric.

The Queen Of The Night, 2019, detail of a jacquard and hand-embroidered tapestry and mural, dimensions variable The Queen Of The Night, 2019, detail of a jacquard and hand-embroidered tapestry and mural, dimensions variable Vitrine, 2018, oil on canvas, 30 x 45 cm The Girl In White, 2018, acrylic and transfer on canvas, 50 x 60 cm, detail Moulid Knight, 2019, oil on paper, 21 x 29.7 cm Babouche, 2019, oil on canvas, 15 x 15 cm Mimi and the Yellow Taxi, 2018, oil on canvas, 60 x 80 cm Summer Blues, 2019, hand-embroidered tapestry on canvas, 25 x 22 cm

HEND SAMIR

"In my new paintings one of the main themes has been juxtaposing innocence with scandal and I find myself delving deeper into this idea and questioning the ways in which we encounter or create 'a scandal.' This phenomenon has become ever-present in this age of the internet and fast-traveling information. We see the scandals of people we've never met, based on the opinions of other anonymous people. Often the phrasing of a headline is what makes the event what it is. Masses are consuming these revealing stories, as the media perpetuates their appetite. The power of a scandal relies on the threat of disclosure to the public or on the revelation of contradictions and secrets that stoke people's curiosity. Just like all ceremonial rituals, it needs an audience. My works build on the investigation of what is hidden and what is revealed -in social, familial contexts, and human relationships. It is the extremities of both contrasts that interests me most."

Hend Samir superimposes layers of desire, adventure, and fantasy onto seemingly ordinary familial contexts. Using acrylic paint on canvas, she constructs her scenes like collages, mixing elements from personal family photos with those of strangers in magazines and internet imagery. The theatricality of her compositions seeps into the characters' psyche, as her characters "act normal" with awareness of being viewed, like in reality TV shows, but in this case, the artist takes on the role of director. Her work also explores the various forms of adventures that can be sought in urban spaces with limited resources, chasing the spirit of children making fortresses out of bed sheets. The physicality of these little adventurous activities, their randomness and their penchant for absurdity are captured within a timeless space, where old and contemporary images are cards in the same game. Her maze-like compositions invite the viewer to maneuver and engage in that layer of playfulness. How is it made, perceived, visualized, and understood? This interest came from a growing consciousness that historical narratives are not given but rather produced in part by an ongoing engagement with an institution such as an archive. I developed my method of looking into the past by digging for what happened during historical events, searching for forgotten episodes, detecting through information that was never on the surface, or collecting testimony from people who witnessed a particular event; this process combines the idea of a storyteller with a history-teller.

In my work Observational Desire on a Memory that Remains, I was interested in looking at the Palestinian art archive during the seventies and eighties. I went to several art institutions seeking their archives and realized that there is no archive in most of them as they were established after the Oslo agreement in 1993. From this point, I started to imagine the past rather than searching for institutional documents.

The process started by interviewing people who lived/witnessed the past, looking at their personal archives, and trying to create a network of people who might give information about the history. This information is the source of the work's narratives.

The work is an attempt to create an imaginary archive of the art history of Palestine.

The history of art significantly predates the presence of art institutions themselves in Palestine: there is a big gap that isn't documented. Imagination is my solution to recovering and rewriting the archive."