Eleftherios PapachristosChange photo
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  • University of Patras
    Electrical and Computer Engineering Department
    Section of Electronics and Computers
    GR - 26500 Rio, Patras, GREECE
  • +302610996868 +302610997304
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Effective and efficient usability evaluation methodologies are required in order to develop and maintain software applications that meet user requirements and expectations. This is particularly relevant to applications that change... more
Effective and efficient usability evaluation methodologies are required in order to develop and maintain software applications that meet user requirements and expectations. This is particularly relevant to applications that change frequently during their lifecycle. Remote usability evaluation provides such a solution. Numerous approaches and techniques have been proposed to allow remote usability evaluation of software applications, and the purpose of this paper is to categorize and evaluate these approaches. We also discuss relevant issues such as user data collection and analysis. After surveying the proposed approaches and identifying pros and cons, we conclude with promising directions for future research in this area.
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This paper investigates whether users’ aesthetic impressions about websites vary considerably across different domains. The assumption that aesthetic judgments about websites that belong to diverse domains are based on different visual... more
This paper investigates whether users’ aesthetic impressions about websites vary considerably across different domains. The assumption that aesthetic judgments about websites that belong to diverse domains are based on different visual design aspects has been investigated in three distinct studies in healthcare, tourism, and web design business. In these studies participants expressed their overall preference as well as their judgments on the constructs of visual appeal, perceived usability and novelty. In addition, descriptions about the test websites were obtained by expert panel and objective measures. Preference Mapping (PM), which is a data summarization and visualization technique, has been performed in each study. Attribute projection into the preference maps allowed for the identification of important driver of preference for each individual domain. Even though, visual appeal was the most important predictor of overall preference in all studies, appealing websites had different visual characteristics in each domain. Furthermore the importance of the evaluation constructs varied considerably among studies, indicating that aesthetic perceptions differed considerably across domains. These findings emphasize the need for flexible evaluation methods that can be used to identify important visual design factors within a specific website domain.
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This paper investigates whether immediate impression about websites influences only perceptions of attractiveness. The evaluative constructs of perceived usability, credibility and novelty were investigated alongside visual appeal in an... more
This paper investigates whether immediate impression about websites influences only perceptions of attractiveness. The evaluative constructs of perceived usability, credibility and novelty were investigated alongside visual appeal in an experimental setting in which users evaluated 20 website screenshots in two phases. The websites were rated by the participants after viewing time of 500 ms in the first phase and with no time limit in the second. Withinwebsite and within-rater consistency were examined in order to determine whether extremely short time period are enough to quickly form stable opinions about high level evaluative constructs besides visual appeal. We confirmed that quick and stable visual appeal judgments were made without the need of elaborate investigations and found evidence that this is also true for novelty. Usability and credibility judgments were found less consistent but nonetheless noteworthy.
The objective of this study was to apply a technique called preference mapping to the context of aesthetic website evaluation. Preference mapping is a method in which evaluators and stimuli are simultaneously represented in the same... more
The objective of this study was to apply a technique called preference mapping to the context of aesthetic website evaluation. Preference mapping is a method in which evaluators and stimuli are simultaneously represented in the same multidimensional space. User segmentations and drivers of preference can easily be identified. We argue that this technique is particularly suited for website design evaluation especially for alternative prototype comparisons. The application of this method to an actual dataset resulted in a better understanding of participant preferences that could not be reached through simple comparison of average ratings.
This paper explores the possibility to predict positive aesthetic impression and user preference of website design through a combination of objective and subjective factors. The objective factors used are symmetry, order, balance,... more
This paper explores the possibility to predict positive aesthetic impression and user preference of website design through a combination of objective and subjective factors. The objective factors used are symmetry, order, balance, complexity while the subjective ones include familiarity - novelty ratings. The advantages of such an approach is the reduction of user involvement since the ratings of objective factors may be provided by a small number of design experts. We found indications that balance between certain factors maximize the possibility of users having a positive aesthetic impression.
In this paper, a novel methodology for selecting appropriate color scheme for a web site is presented. The methodology uses a machine learning algorithm for generating a network that relates the color model of a web site with the... more
In this paper, a novel methodology for selecting appropriate color scheme for a web site is presented. The methodology uses a machine learning algorithm for generating a network that relates the color model of a web site with the emotional values that are attributed to it by its users. The approach involves an empirical study to collect data, used to train the algorithm. A preliminary case study has been conducted to validate the applicability of the methodology. Description of the framework and a set of tools that were built to support the methodology is also included.
Effective and efficient usability evaluation methodologies are required in order to develop and maintain software applications that meet user requirements and expectations. This is particularly relevant to applications that change... more
Effective and efficient usability evaluation methodologies are required in order to develop and maintain software applications that meet user requirements and expectations. This is particularly relevant to applications that change frequently during their lifecycle. Remote usability evaluation provides such a solution. Numerous approaches and techniques have been proposed to allow remote usability evaluation of software applications, and the purpose of this paper is to categorize and evaluate these approaches. We also discuss relevant issues such as user data collection and analysis. After surveying the proposed approaches and identifying pros and cons, we conclude with promising directions for future research in this area.
Color plays an important role in web site design. The selection of effective chromatic combinations and the relation of color to the perceived aesthetic and emotional value of a web site is the focus of this paper. The subject of the... more
Color plays an important role in web site design. The selection of effective chromatic combinations and the relation of color to the perceived aesthetic and emotional value of a web site is the focus of this paper. The subject of the reported research has been to define a model through which to be able to associate color combinations with specific desirable emotional and aesthetic values. The presented approach involves application of machine learning techniques on a rich data set collected during a number of empirical studies.
In this paper, a novel methodology for selecting appropriate color scheme for a web site is presented. The methodology uses a machine learning algorithm for generating a network that relates the color model of a web site with the... more
In this paper, a novel methodology for selecting appropriate color scheme for a web site is presented. The methodology uses a machine learning algorithm for generating a network that relates the color model of a web site with the emotional values that are attributed to it by its users. The approach involves an empirical study to collect data, used to train the algorithm. A preliminary case study has been conducted to validate the applicability of the methodology. Description of the framework and a set of tools that were built to support the methodology is also included.
Colour plays an important role in web site design. The selection of effective chromatic combinations and the relation of colour to the perceived aesthetic and emotional value of a web site is the focus of this paper. The subject of the... more
Colour plays an important role in web site design. The selection of effective chromatic combinations and the relation of colour to the perceived aesthetic and emotional value of a web site is the focus of this paper. The subject of the reported research has been to define a model through which to be able to associate colour combinations with specific desirable emotional and aesthetic values. The presented approach involves application of machine learning techniques on a rich data set collected during a number of empirical studies. The data obtained were used to train a Bayesian Belief Network which associated a simple chromatic model to perceived aesthetic and emotional dimensions. A set of tools that have been build in the process to support the methodological framework and ensure its reusability with minimal effort, are also describe
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The usability is recognized as an important quality factor of any modern website. In this paper, techniques for usability evaluation of a website are proposed and their use is described. The results of application of these techniques are... more
The usability is recognized as an important quality factor of any modern website. In this paper, techniques for usability evaluation of a website are proposed and their use is described. The results of application of these techniques are discussed in the frame of the design and evaluation of a web portal, serving an Academic Department. The applicability of the developed techniques in a wide area of web-based applications and their importance in the context of today’s web applications development is also discussed in this paper.
"The main goal of this thesis is to propose an evaluation method for visual interface design and more specifically for website design. The proposed visual design evaluation method is an adaptation of Preference Mapping techniques. It is... more
"The main goal of this thesis is to propose an evaluation method for visual interface design and more specifically for website design. The proposed visual design evaluation method is an adaptation of Preference Mapping techniques. It is based on overall preference ratings after multiple comparisons of alternative designs and on various multivariate statistical techniques for the analysis, visualization and interpretation of the resulting data. The suitability of the approach for visual interface design evaluation has been explored in four case studies involving overall 149 participants judging 51 websites. In each case study a different website domain was explored in order to examine whether the importance of certain design aspects is context specific. Heterogeneity in preferences and perceptions was also studied showing that average construct scores are only representative for subsections of the participant sample. For preference interpretation purposes three distinct sources of external information have been studied:
• Subjective construct ratings provided by the participants after preference evaluation
• Descriptive attribute ratings obtained from trained expert panel on the same websites
• Objective measures of visual characteristics of the websites
In each case study the potential of these external information sources to explain preference variance has been investigated individually and in combination. The results showed that varying combinations of external information sources had the best explanatory power, depending on the amount of variation within each website sample. In regard to preference mapping techniques, both approaches, namely internal and external analysis, have been applied to each case study in order to identify the advantages of one over the other in the context of visual website evaluation. In addition, different statistical techniques have been tried in order to produce the preference or perceptual maps such us Principal Component Analysis (PCA), Generalized Procrustes Analysis (GPA) and Partial Least Squares (PLS) in order to identify the most appropriate technique for each case. 
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