Browsing by Author "Bin Amer, Hadeel Hatim"

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Open Access
A Linear Model for Three-Way Analysis of Facial Similarity
(Springer, Cham, 2018-05-18) Hepting, Daryl H.; Bin Amer, Hadeel Hatim; Yao, Yiyu
Card sorting was used to gather information about facial similarity judgments. A group of raters put a set of facial photos into an unrestricted number of different piles according to each rater’s judgment of similarity. This paper proposes a linear model for 3-way analysis of similarity. An overall rating function is a weighted linear combination of ratings from individual raters. A pair of photos is considered to be similar, dissimilar, or divided, respectively, if the overall rating function is greater than or equal to a certain threshold, is less than or equal to another threshold, or is between the two thresholds. The proposed framework for 3-way analysis of similarity is complementary to studies of similarity based on features of photos.
Open Access
A Probabilistic Approach to Card Sort Analysis
(Faculty of Graduate Studies and Research, University of Regina, 2018-02) Bin Amer, Hadeel Hatim; Hepting, Daryl; Hilderman, Robert; Butz, Cortney J.; Zhao, Yang; Deif, Ahmed
The work in this dissertation was motivated by the desire to more fully understand the results of a card sorting study of facial photographs. Twenty-five participants were asked to sort 356 facial photographs (178 of Caucasian males and 178 of First Nations’ males) into an unconstrained number of piles according to their judgments of similarity. Researchers have used card sorting to understand different concepts, but not facial similarity. Therefore, the work presented in the dissertation is novel because it takes an existing method and applies it to a new context and adapts analysis tools to this purpose. Pairs of photos in the same pile were deemed to be judged “similar” and those in different piles were deemed to be judged “dissimilar”. There are 63,190 pairs possible from 356 photos. It is clear that participants did not, nor could not, make all these pairwise comparisons directly. The study was executed, analyzed, and described by other researchers at the University of Regina, but there remain unresolved questions from the data that it produced. Some participants made very few piles which others made very many: should the information provided by each participant be treated equally? Is there enough information in the sorting of the cards to uncover how participants have judged facial similarity, with different participants using possibly different strategies? Perhaps it would be more productive to work with a smaller number of photos, but how should these photos be selected and what number of photos is neither “too many” nor “too few”? If the majority of participants agree that a photo pair is similar or dissimilar, that pair may not help to discern different strategies that participants may be using. Therefore, it is possible to consider the data in terms of a three-way decision: if 16 or more of the 25 participants judged a pair to be similar, the pair is labelled as Similar. If 9 or fewer of the 25 participants judged a pair to be similar, the pair is labelled as Dissimilar. Finally, if between 10 and 15 participants judged the pair to be similar, the pair is labelled as Undecided. In order to explore the questions about information quality, the probability of each pair of photos was calculated, modelled as the first two photos drawn from a deck without replacement. If a participant placed the pair with many other photos, either together in one pile or apart in two piles, the probability of that pair was large. Alternatively, the probability of the pair was small if it was placed with few other photos. The probability of the pair is hypothesized to be an indicator of confidence: a small probability means high confidence and a large probability means low confidence. If the Undecided group contains photo pairs about which some participants are very confident of similarity and others are very confident of dissimilarity, these pairs may be most useful to study further. The eigenface method of evaluating facial similarity was used to provide a reference for the judgements made in the card sorting study. The Euclidean distance between each pair projected photos was used as a surrogate for the similarity judgements: pairs with small intra-pair distances were deemed to be judged “similar” and pairs with large intra-pair distances were deemed to be judged “dissimilar”. A second study was conducted, based the analysis of the first, that asked forty-three participants to rate the similarity of selected photo pairs on a scale from 0 (Similar) to 100 (Dissimilar), with the midpoint representing Undecided. Analysis of the second, pairwise, study found agreement with the first, card-sorting, study. The application of the 3-way decision framework also proved valuable. In conclusion, the work has provided a means, previously unavailable, to understand the importance of various photo pairs in participants’ judgment of similarity.
Open Access
Three-Way Analysis of Facial Similarity Judgments
(2017-10-23) Hepting, Daryl H.; Bin Amer, Hadeel Hatim; Yao, Yiyu
The card sorting problem involves the similarity judgments of pairs of photos, taken from a set of photos, by a group of participants. Given the lack of an objective standard for judging similarity, different participants may be using different strategies in judging the similarity of photos. It could be very useful to identify and study these strategies. In this paper, we present a framework for three-way analysis of judgments of similarity. Based on judgments by the set of participants, we divide all pairs of photos into three classes: a set of similar pairs that are judged by at least 60% of participants as similar; a set of dissimilar pairs that are judged by at least 60% of participants as dissimilar; and a set of undecidable pairs that have conflicting judgments. A more refined three-way classification method is also suggested based on a quantitative description of the quality of similarity judgments. The classification in terms of three classes provides an effective method to examine the notions of similarity, dissimilarity, and disagreement.